synced 11 MIN AGO
01 Record

CVE-2026-93990

Expat before 2.8.5 Malformed UTF-16 Acceptance via Unchecked Surrogate

HighPUBLISHEDCNA: VulnCheck
CNA base score8.7 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
View raw JSON

02 Description

Expat before 2.8.5 Malformed UTF-16 Acceptance via Unchecked Surrogate

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.
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
0.40% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 34.3% 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:H/VA:N/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
Awaiting Analysis. NVD last modified this record on 2026-09-28.
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
2026-09-19 22:58Z1 MO AGO
Last updated
2026-09-28 16:11Z1 MO AGO
Reserved
2026-09-19
Assigning CNA
VulnCheck
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:H/VA:N/SC:N/SI:N/SA:N
Weaknesses
  • CWE-176Improper Handling of Unicode EncodingVariant
Data version
5.2
Document digest
b312ac62b2af19266e0d543be380134209b6fe4c21836cfcebae5ed4fb761b26

05 Affected products

VendorProductVersionsPlatforms
libexpatlibexpat0 to < 2.8.5—

06 References

07 Fixed in

AlmaLinux 8

  • expat
    Fixed in 2.5.0-4.el8_10
  • expat-devel
    Fixed in 2.5.0-4.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

  • expat
    Fixed in 2.5.0-6.el9_8.5
  • expat-devel
    Fixed in 2.5.0-6.el9_8.5

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

AlmaLinux 10

  • expat
    Fixed in 2.7.3-1.el10_2.5
  • expat-devel
    Fixed in 2.7.3-1.el10_2.5

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

CloudLinux 8

  • expat
    Fixed in 2.5.0-4.el8_10
  • expat-devel
    Fixed in 2.5.0-4.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

  • expat
    Fixed in 2.5.0-6.el9_8.5
  • expat-devel
    Fixed in 2.5.0-6.el9_8.5

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

  • expat
    Fixed in 2.7.3-1.el10_2.5
  • expat-devel
    Fixed in 2.7.3-1.el10_2.5

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

  • expat
    Fixed in 2.5.0-1+deb12u4

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

Debian 13

  • expat
    Fixed in 2.9.0-1~deb13u1

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

Debian 14

  • expat
    Fixed in 2.8.4-2

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

Ubuntu 16.04 LTS

  • cadaver
    No fix yet
  • gdcm
    No fix yet
  • insighttoolkit4
    No fix yet
  • matanza
    No fix yet
  • smart
    No fix yet
  • tdom
    No fix yet
  • wbxml2
    No fix yet

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

Ubuntu 18.04 LTS

  • cadaver
    No fix yet
  • gdcm
    No fix yet
  • insighttoolkit4
    No fix yet
  • matanza
    No fix yet
  • smart
    No fix yet
  • tdom
    No fix yet
  • vnc4
    No fix yet
  • wbxml2
    No fix yet

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

Ubuntu 20.04 LTS

  • cadaver
    No fix yet
  • insighttoolkit4
    No fix yet
  • matanza
    No fix yet
  • tdom
    No fix yet
  • wbxml2
    No fix yet

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

Ubuntu 22.04 LTS

  • cadaver
    No fix yet
  • expat
    No fix yet
  • insighttoolkit4
    No fix yet
  • matanza
    No fix yet
  • tdom
    No fix yet
  • wbxml2
    No fix yet

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

Ubuntu 24.04 LTS

  • cadaver
    No fix yet
  • expat
    No fix yet
  • matanza
    No fix yet
  • tdom
    No fix yet
  • wbxml2
    No fix yet

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

Ubuntu 26.04 LTS

  • cadaver
    No fix yet
  • expat
    No fix yet
  • matanza
    No fix yet
  • tdom
    No fix yet
  • wbxml2
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu 26.10

  • cadaver
    No fix yet
  • expat
    No fix yet
  • matanza
    No fix yet
  • swish-e
    No fix yet
  • tdom
    No fix yet
  • wbxml2
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu Pro 14.04 LTS

  • coin3
    No fix yet
  • expat
    No fix yet
  • vnc4
    No fix yet
  • vtk
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu Pro 16.04 LTS

  • ayttm
    No fix yet
  • cableswig
    No fix yet
  • coin3
    No fix yet
  • expat
    No fix yet
  • libxmltok
    No fix yet
  • swish-e
    No fix yet
  • vnc4
    No fix yet
  • vtk
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu Pro 18.04 LTS

  • coin3
    No fix yet
  • expat
    No fix yet
  • libxmltok
    No fix yet
  • swish-e
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu Pro 20.04 LTS

  • expat
    No fix yet
  • libxmltok
    No fix yet
  • swish-e
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu Pro 22.04 LTS

  • libxmltok
    No fix yet
  • swish-e
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu Pro 24.04 LTS

  • libxmltok
    No fix yet
  • swish-e
    No fix yet
  • xmlrpc-c
    No fix yet

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

Ubuntu Pro 26.04 LTS

  • swish-e
    No fix yet

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.