CVE-2026-44375
CVE-2026-44375 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-789.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 0% (29th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-30299
- Weakness: CWE-789
- Published:
- Last modified:
Description
Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the reader to allocate an attacker-controlled number of bytes on the stack. This can trigger a StackOverflowException, which is not catchable by user code and terminates the process. This vulnerability is fixed in 1.1.62.
Frequently asked questions
- What is CVE-2026-44375?
- Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the reader to allocate an attacker-controlled number of bytes on the stack. This can trigger a StackOverflowException, which is not catchable by user code and terminates the process. This vulnerability is fixed in 1.1.62.
- How severe is CVE-2026-44375?
- CVE-2026-44375 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-44375 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-44375?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-44375 have an EU (EUVD) identifier?
- Yes. CVE-2026-44375 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30299.
- When was CVE-2026-44375 published?
- CVE-2026-44375 was published on 2026-05-14 and last updated on 2026-06-17.
References
- https://github.com/AArnott/Nerdbank.MessagePack/commit/7d1eb319cfabe7280e70699946c9a48579fa2f30
- https://github.com/AArnott/Nerdbank.MessagePack/pull/941
- https://github.com/AArnott/Nerdbank.MessagePack/releases/tag/v1.1.62
- https://github.com/AArnott/Nerdbank.MessagePack/security/advisories/GHSA-2cwq-pwfr-wcw3
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