CVE-2026-63383: Libevent: decode_tag_internal() can lead to out-of-bounds read
CSIRTS triage
- What
- decode_tag_internal() performs out-of-bounds reads during tag decoding.
- Who is affected
- Libevent applications processing untrusted serialized tag data.
- Urgency
- High; out-of-bounds reads can leak memory or crash the application; prioritize patching.
- Action
- Update Libevent to a patched version; minimize processing of untrusted tag input.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63383
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-633830.38% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 32% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-63383 | coverage & exploitation status | NVD · CVE.org |
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