CVE-2026-124317
libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16
libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- Low
What each source reports
CVE List Score used
libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16
libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.
- Record
CVE-2026-124317- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N - CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - Weakness
- CWE-126
- Updated
- 2026-11-07
EUVDEUVD-2026-119271
libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.
- Record
EUVD-2026-119271- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N - Updated
- 2026-11-07
GitHub AdvisoriesGHSA-wm22-jw4m-rfcf
libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and...
libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.
- Record
GHSA-wm22-jw4m-rfcf- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/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 - CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - Weakness
- CWE-126
- Updated
- 2026-11-07
NVD
libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.
- Record
CVE-2026-124317- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/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 - CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - Weakness
- CWE-126
- Updated
- 2026-11-07
OSVDEBIAN-CVE-2026-124317
- Record
DEBIAN-CVE-2026-124317- CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L - Updated
- 2026-11-07
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
expatDebian:12 |
All versions, plus listed versions 2.10.0-12.5.0-12.5.0-1+deb12u12.5.0-1+deb12u22.5.0-1+deb12u3 Show 32 moreShow less2.5.0-1+deb12u42.5.0-1+deb12u52.5.0-22.6.0-12.6.1-12.6.1-22.6.2-12.6.2-22.6.3-12.6.3-22.6.4-12.7.0-12.7.1-12.7.1-22.7.2-12.7.3-12.7.3-22.7.4-12.7.5-12.8.0-12.8.0-22.8.1-12.8.2-12.8.2-1~deb13u12.8.3-12.8.3-1~deb13u12.8.4-12.8.4-22.8.5-12.8.5-22.9.0-12.9.0-1~deb13u1 |
None known |
expatDebian:13 |
All versions, plus listed versions 2.10.0-12.7.1-22.7.2-12.7.3-12.7.3-2 Show 15 moreShow less2.7.4-12.7.5-12.8.0-12.8.0-22.8.1-12.8.2-12.8.2-1~deb13u12.8.3-12.8.3-1~deb13u12.8.4-12.8.4-22.8.5-12.8.5-22.9.0-12.9.0-1~deb13u1 |
None known |
expatDebian:14 |
All versions, plus listed versions 2.10.0-12.7.1-22.7.2-12.7.3-12.7.3-2 Show 15 moreShow less2.7.4-12.7.5-12.8.0-12.8.0-22.8.1-12.8.2-12.8.2-1~deb13u12.8.3-12.8.3-1~deb13u12.8.4-12.8.4-22.8.5-12.8.5-22.9.0-12.9.0-1~deb13u1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, references | OSV | |
| published | EUVD, NVD | |
| published | EUVD | |
| aliases, references | GitHub Advisories | |
| cwes, products, references, severity, title | CVE List | |
| first indexed | EUVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-124317 is a medium vulnerability (CVSS 6.3) in Libexpat, published November 7, 2026. No source lists public exploit code. No source names a fixed version.
References
github.com/libexpat/libexpat/pull/1492
vulncheck.com/advisories/libexpat-through-2.10.0-out-of-bounds-read-via-unknown-toutf8-and-unknown-toutf16
nvd.nist.gov/vuln/detail/CVE-2026-124317
security-tracker.debian.org/tracker/CVE-2026-124317