synced 6 MIN AGO
01 Record

CVE-2026-63382

libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling

CriticalPUBLISHEDCNA: GitHub_M
CNA base score9.2 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N
View raw JSON

02 Description

libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.78% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 55.7% of scored records. A rank, not a probability.
NVD base score
9.2 (CVSS v4.0), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/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
Awaiting Analysis. NVD last modified this record on 2026-10-26.
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
2026-08-20 17:51Z2 MO AGO
Last updated
2026-08-20 19:33Z2 MO AGO
Reserved
2026-07-16
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
Critical (CVSS 9.2)
CNA CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N
Weaknesses
  • CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')Base
Data version
5.2
Document digest
a4222c8d30643b4dc261b36e3293c8d97e752a10a78ca03e5d2f7b3c482fac09

05 Affected products

VendorProductVersionsPlatforms
libeventlibevent>= 2.2.0-alpha, < 2.2.2-alpha, < 2.1.13—

06 References

07 Fixed in

AlmaLinux 8

  • libevent
    Fixed in 2.1.8-11.el8_10
  • libevent-devel
    Fixed in 2.1.8-11.el8_10
  • libevent-doc
    Fixed in 2.1.8-11.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

  • libevent
    Fixed in 2.1.13-1.el9_8
  • libevent-devel
    Fixed in 2.1.13-1.el9_8
  • libevent-doc
    Fixed in 2.1.13-1.el9_8

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 10

  • libevent
    Fixed in 2.1.13-1.el10_2
  • libevent-devel
    Fixed in 2.1.13-1.el10_2
  • libevent-doc
    Fixed in 2.1.13-1.el10_2

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 8

  • libevent
    Fixed in 2.1.8-11.el8_10
  • libevent-devel
    Fixed in 2.1.8-11.el8_10
  • libevent-doc
    Fixed in 2.1.8-11.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

  • libevent
    Fixed in 2.1.13-1.el9_8
  • libevent-devel
    Fixed in 2.1.13-1.el9_8
  • libevent-doc
    Fixed in 2.1.13-1.el9_8

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

  • libevent
    Fixed in 2.1.13-1.el10_2
  • libevent-devel
    Fixed in 2.1.13-1.el10_2
  • libevent-doc
    Fixed in 2.1.13-1.el10_2

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

  • libevent
    Fixed in 2.1.12-stable-8+deb12u1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • libevent
    Fixed in 2.1.13-stable-1~deb13u1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • libevent
    Fixed in 2.1.13-stable-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • libevent
    Fixed in 2.1.12-stable-1ubuntu0.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 24.04 LTS

  • libevent
    Fixed in 2.1.12-stable-9ubuntu2.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 26.04 LTS

  • libevent
    Fixed in 2.1.12-stable-10ubuntu0.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 14.04 LTS

  • libevent
    Fixed in 2.0.21-stable-1ubuntu1.14.04.2+esm1
    Available 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

  • libevent
    Fixed in 2.0.21-stable-2ubuntu0.16.04.1+esm1
    Available 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

  • libevent
    Fixed in 2.1.8-stable-4ubuntu0.1~esm1
    Available with Ubuntu Pro (Infra-only): 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

  • libevent
    Fixed in 2.1.11-stable-1ubuntu0.1~esm1
    Available with Ubuntu Pro (Infra-only): 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.