PatchTheCEVCVE-2026-72522: libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are treated
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Routine
MEDIUM 6.2
CVE-2026-72522 is a medium-severity flaw (CVSS 6.2) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are treated the same as high surrogates during Unicode processing in the *_toUtf16 functions.
Why this priority
- No elevated risk signals yet
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 6.2 (Medium) |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.2% (top 92%) |
| CISA exploited list | No |
| Weakness | CWE-125 |
| Published | 2026-08-10 |
| Last modified | 2026-10-23 |
Publisher (CNA): MITRE
Timeline
- Published CVE record published
- Updated Record last modified
Advisories and coverage
Official advisories
- Amazon Linux 2 ALAS: ALAS2-2026-3880 (important): thunderbird 2026-08-31
- Amazon Linux 2 ALAS: ALAS2FIREFOX-2026-064 (important): firefox 2026-08-31
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.