Vulnerability · CVE-2026-25210
In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.
Published Jan 30, 2026 · catalog updated Jun 2, 2026 · libexpat project
Last checked Nov 8, 2026. A connected source was read within the last 7 days.
Check if you run it
No confirmed exploitation is on record for CVE-2026-25210. EPSS is 0.21%. Act only if a listed version of libexpat project is installed.
Gaps on this record
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
Same product and reporting
- CVE-2026-115506 · High
- CVE-2026-41080 · Low
- CVE-2026-32778 · Medium
- CVE-2026-32777 · Medium
- CVE-2026-32776 · Medium
- Severity
- Medium6.9
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.21%
- Remediation
- Version ranges on file
- Affected products
- vendor libexpat project libexpat 0 <2.7.4
In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- vendor libexpat project libexpat 0 <2.7.40 <2.7.4
How to fix CVE-2026-25210
Upgrade
CVE-2026-25210 lists a fix boundary at 2.7.4. Compare the installed build with that boundary before you change production.
Version check
Seen in 0 <2.7.4
Advisory
Open the cve_org record and follow its fix.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-25210. EPSS is 0.21%. Act only if a listed version of libexpat project is installed.
Which versions are affected?
Compare what you have installed with libexpat project libexpat 0 <2.7.4 0 <2.7.4. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS 0.21%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Jan 30, 2026 · EUVD
Detected
In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.
Jun 2, 2026 · EUVD
Updated
In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.
Sources
- CVE.orgVulnerability recordCVE-2026-25210
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-25210
30-day exploitation probability 0.21%
first.org - EUVDVulnerability recordEUVD-2026-5042
In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.
euvd.enisa.europa.eu
References
Freshness
Last verified in this catalog Nov 8, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.
- FIRST EPSSNov 8, 2026
- CVE.orgNov 4, 2026
- EUVDNov 2, 2026