CVE-2026-15308
Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations
02 Description
Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.63% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 50.3% of scored records. A rank, not a probability.
- NVD base score
- 8.7 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVD analysis status
- Analyzed. NVD last modified this record on 2026-10-25.
- Red Hat severity
- Important. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-07-09 17:10Z3 MO AGO
- Last updated
- 2026-08-13 00:28Z2 MO AGO
- Reserved
- 2026-07-09
- Assigning CNA
- PSF
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.7)
- CNA CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Weaknesses
- Data version
- 5.2
- Document digest
- 4827abf93a22435df8eb46b7112a0b15d1c477ce482b0575e7a29a4f6a17b920
05 Affected products
06 References
- mail.python.orghttps://mail.python.org/archives/list/security-announce@python.org/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5/
- github.comhttps://github.com/python/cpython/pull/153031
- github.comhttps://github.com/python/cpython/issues/153030
- github.comhttps://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9
- github.comhttps://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced
- github.comhttps://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606
- github.comhttps://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd
- github.comhttps://github.com/python/cpython/commit/785df8f743800661961528970f8598edcd291c14
- github.comhttps://github.com/python/cpython/commit/1e7956f1a722df9aabc509c30f8fbdc3a2b4fdc7
- github.comhttps://github.com/python/cpython/commit/c2390b9376e35a701ed3acc597b8fc87546c9b00
- www.openwall.comhttp://www.openwall.com/lists/oss-security/2026/07/09/4
07 Fixed in
AlmaLinux 8
- platform-python Fixed in 3.6.8-77.el8_10.alma.1
- platform-python-debug Fixed in 3.6.8-77.el8_10.alma.1
- platform-python-devel Fixed in 3.6.8-77.el8_10.alma.1
- python3-idle Fixed in 3.6.8-77.el8_10.alma.1
- python3-libs Fixed in 3.6.8-77.el8_10.alma.1
- python3-test Fixed in 3.6.8-77.el8_10.alma.1
- python3-tkinter Fixed in 3.6.8-77.el8_10.alma.1
- python3.12 Fixed in 3.12.13-3.el8_10
- python3.12-debug Fixed in 3.12.13-3.el8_10
- python3.12-devel Fixed in 3.12.13-3.el8_10
- python3.12-idle Fixed in 3.12.13-3.el8_10
- python3.12-libs Fixed in 3.12.13-3.el8_10
- python3.12-rpm-macros Fixed in 3.12.13-3.el8_10
- python3.12-test Fixed in 3.12.13-3.el8_10
- python3.12-tkinter Fixed in 3.12.13-3.el8_10
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 9
- python-unversioned-command Fixed in 3.9.25-7.el9_8.2
- python3 Fixed in 3.9.25-7.el9_8.2
- python3-debug Fixed in 3.9.25-7.el9_8.2
- python3-devel Fixed in 3.9.25-7.el9_8.2
- python3-idle Fixed in 3.9.25-7.el9_8.2
- python3-libs Fixed in 3.9.25-7.el9_8.2
- python3-test Fixed in 3.9.25-7.el9_8.2
- python3-tkinter Fixed in 3.9.25-7.el9_8.2
- python3.12 Fixed in 3.12.13-3.el9_8.1
- python3.12-debug Fixed in 3.12.13-3.el9_8.1
- python3.12-devel Fixed in 3.12.13-3.el9_8.1
- python3.12-idle Fixed in 3.12.13-3.el9_8.1
- python3.12-libs Fixed in 3.12.13-3.el9_8.1
- python3.12-test Fixed in 3.12.13-3.el9_8.1
- python3.12-tkinter Fixed in 3.12.13-3.el9_8.1
- python3.14 Fixed in 3.14.5-1.el9_8.1
- python3.14-debug Fixed in 3.14.5-1.el9_8.1
- python3.14-devel Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-debug Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-devel Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-idle Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-libs Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-test Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-tkinter Fixed in 3.14.5-1.el9_8.1
- python3.14-idle Fixed in 3.14.5-1.el9_8.1
- python3.14-libs Fixed in 3.14.5-1.el9_8.1
- python3.14-test Fixed in 3.14.5-1.el9_8.1
- python3.14-tkinter Fixed in 3.14.5-1.el9_8.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 10
- python-unversioned-command Fixed in 3.12.13-2.el10_2.1
- python3 Fixed in 3.12.13-2.el10_2.1
- python3-debug Fixed in 3.12.13-2.el10_2.1
- python3-devel Fixed in 3.12.13-2.el10_2.1
- python3-idle Fixed in 3.12.13-2.el10_2.1
- python3-libs Fixed in 3.12.13-2.el10_2.1
- python3-test Fixed in 3.12.13-2.el10_2.1
- python3-tkinter Fixed in 3.12.13-2.el10_2.1
- python3.14 Fixed in 3.14.5-1.el10_2.1
- python3.14-debug Fixed in 3.14.5-1.el10_2.1
- python3.14-devel Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-debug Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-devel Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-idle Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-libs Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-test Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-tkinter Fixed in 3.14.5-1.el10_2.1
- python3.14-idle Fixed in 3.14.5-1.el10_2.1
- python3.14-libs Fixed in 3.14.5-1.el10_2.1
- python3.14-test Fixed in 3.14.5-1.el10_2.1
- python3.14-tkinter Fixed in 3.14.5-1.el10_2.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 8
- platform-python Fixed in 3.6.8-77.el8_10.alma.1
- platform-python-debug Fixed in 3.6.8-77.el8_10.alma.1
- platform-python-devel Fixed in 3.6.8-77.el8_10.alma.1
- python3-idle Fixed in 3.6.8-77.el8_10.alma.1
- python3-libs Fixed in 3.6.8-77.el8_10.alma.1
- python3-test Fixed in 3.6.8-77.el8_10.alma.1
- python3-tkinter Fixed in 3.6.8-77.el8_10.alma.1
- python3.12 Fixed in 3.12.13-3.el8_10
- python3.12-debug Fixed in 3.12.13-3.el8_10
- python3.12-devel Fixed in 3.12.13-3.el8_10
- python3.12-idle Fixed in 3.12.13-3.el8_10
- python3.12-libs Fixed in 3.12.13-3.el8_10
- python3.12-rpm-macros Fixed in 3.12.13-3.el8_10
- python3.12-test Fixed in 3.12.13-3.el8_10
- python3.12-tkinter Fixed in 3.12.13-3.el8_10
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 9
- python-unversioned-command Fixed in 3.9.25-7.el9_8.2
- python3 Fixed in 3.9.25-7.el9_8.2
- python3-debug Fixed in 3.9.25-7.el9_8.2
- python3-devel Fixed in 3.9.25-7.el9_8.2
- python3-idle Fixed in 3.9.25-7.el9_8.2
- python3-libs Fixed in 3.9.25-7.el9_8.2
- python3-test Fixed in 3.9.25-7.el9_8.2
- python3-tkinter Fixed in 3.9.25-7.el9_8.2
- python3.12 Fixed in 3.12.13-3.el9_8.1
- python3.12-debug Fixed in 3.12.13-3.el9_8.1
- python3.12-devel Fixed in 3.12.13-3.el9_8.1
- python3.12-idle Fixed in 3.12.13-3.el9_8.1
- python3.12-libs Fixed in 3.12.13-3.el9_8.1
- python3.12-test Fixed in 3.12.13-3.el9_8.1
- python3.12-tkinter Fixed in 3.12.13-3.el9_8.1
- python3.14 Fixed in 3.14.5-1.el9_8.1
- python3.14-debug Fixed in 3.14.5-1.el9_8.1
- python3.14-devel Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-debug Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-devel Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-idle Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-libs Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-test Fixed in 3.14.5-1.el9_8.1
- python3.14-freethreading-tkinter Fixed in 3.14.5-1.el9_8.1
- python3.14-idle Fixed in 3.14.5-1.el9_8.1
- python3.14-libs Fixed in 3.14.5-1.el9_8.1
- python3.14-test Fixed in 3.14.5-1.el9_8.1
- python3.14-tkinter Fixed in 3.14.5-1.el9_8.1
Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 10
- python-unversioned-command Fixed in 3.12.13-2.el10_2.1
- python3 Fixed in 3.12.13-2.el10_2.1
- python3-debug Fixed in 3.12.13-2.el10_2.1
- python3-devel Fixed in 3.12.13-2.el10_2.1
- python3-idle Fixed in 3.12.13-2.el10_2.1
- python3-libs Fixed in 3.12.13-2.el10_2.1
- python3-test Fixed in 3.12.13-2.el10_2.1
- python3-tkinter Fixed in 3.12.13-2.el10_2.1
- python3.14 Fixed in 3.14.5-1.el10_2.1
- python3.14-debug Fixed in 3.14.5-1.el10_2.1
- python3.14-devel Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-debug Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-devel Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-idle Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-libs Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-test Fixed in 3.14.5-1.el10_2.1
- python3.14-freethreading-tkinter Fixed in 3.14.5-1.el10_2.1
- python3.14-idle Fixed in 3.14.5-1.el10_2.1
- python3.14-libs Fixed in 3.14.5-1.el10_2.1
- python3.14-test Fixed in 3.14.5-1.el10_2.1
- python3.14-tkinter Fixed in 3.14.5-1.el10_2.1
Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- python3.11 Fixed in 3.11.2-6+deb12u9
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- python3.13 No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- python3.13 Fixed in 3.13.15-1
- python3.14 Fixed in 3.14.7-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- python3.10 Fixed in 3.10.12-1~22.04.18
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- python3.12 Fixed in 3.12.3-1ubuntu0.17
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 26.04 LTS
- python3.14 Fixed in 3.14.4-1ubuntu0.2
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- python2.7 Fixed in 2.7.6-8ubuntu0.6+esm30Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
- python3.4 Fixed in 3.4.3-1ubuntu1~14.04.7+esm21Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
- python3.5 Fixed in 3.5.2-2ubuntu0~16.04.4~14.04.1+esm11Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- python2.7 Fixed in 2.7.12-1ubuntu0~16.04.18+esm22Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
- python3.5 Fixed in 3.5.2-2ubuntu0~16.04.13+esm25Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 18.04 LTS
- python2.7 Fixed in 2.7.17-1~18.04ubuntu1.13+esm15Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- python3.6 Fixed in 3.6.9-1~18.04ubuntu1.13+esm10Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- python3.7 Fixed in 3.7.5-2ubuntu1~18.04.2+esm11Available with Ubuntu Pro: https://ubuntu.com/pro
- python3.8 Fixed in 3.8.0-3ubuntu1~18.04.2+esm11Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 20.04 LTS
- python3.8 Fixed in 3.8.10-0ubuntu1~20.04.18+esm7Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- python3.9 Fixed in 3.9.5-3ubuntu0~20.04.1+esm11Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 22.04 LTS
- python2.7 Fixed in 2.7.18-13ubuntu1.5+esm9Available with Ubuntu Pro: https://ubuntu.com/pro
- python3.11 Fixed in 3.11.0~rc1-1~22.04.1+esm2Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.