libexpat is a widely used XML library; the bug leaks heap/libc/code pointers enabling ASLR bypass and exploit chains across many dependent applications.
CVE-2026-77214
libexpat heap over-read leaks pointers, enabling ASLR bypass and exploit chains.
Is CVE-2026-77214 being exploited?
Not confirmed. CVE-2026-77214 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.55% probability of exploitation in the next 30 days.
How severe is CVE-2026-77214?
CVE-2026-77214 is rated High with a CVSS score of 8.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-77214?
Yes. A fix has been recorded for CVE-2026-77214. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-77214 affect?
CVE-2026-77214 affects libexpat (versions before commit 13c5f63), Applications embedding libexpat, Software stacks and libraries that vendor-bundle expat. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-77214?
Update to commit 13c5f63+ or vendor patch; rebuild/redeploy affected binaries.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Heap buffer over-read discloses heap/libc/code pointers, defeats ASLR and enables attackers to build RCE or further exploitation primitives.
Patch when possible
- affected<= 2.8.5
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.