CVE-2026-42327

HIGHNVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 89% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
8.7
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.7 to before 0.10.79, X509Ref::ocsp_responders returns OCSP responder URLs from a certificate's AIA extension as OpensslString, whose Deref wraps the raw bytes with str::from_utf8_unchecked. OpenSSL does not enforce that the underlying IA5String is ASCII, so a certificate with non-UTF-8 bytes in its OCSP accessLocation causes safe Rust code to construct a &str that violates the UTF-8 invariant — resulting in undefined behavior. This vulnerability is fixed in 0.10.79.

CVSS v3
8.7
EG Score
8.7(medium)
EPSS
11.3%
KEV
Not listed

Published

May 14, 2026

Last Modified

May 15, 2026

Advisory Details (1)

Auto-updated May 14, 2026
Patch available. Sources: github.
github Patch Available

undefined behavior in X509Ref::ocsp_responders for certificates with non-UTF-8 OCSP URLs · Advisory · rust-openssl/rust-openssl · GitHub

https://github.com/rust-openssl/rust-openssl/security/advisories/GHSA-xp3w-r5p5-63rr

Vendor Advisories for CVE-2026-42327(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
crates.io(1)
PackageVulnerable rangeFixed inDependents
openssl—0.10.79—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 113 total refreshes for this CVE.

  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:15 UTCEPSS rescore
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  13. 2026-06-29 21:41 UTCEG score recompute
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  1. 2026-06-23 21:33 UTCEPSS rescore
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  10. 2026-06-18 04:25 UTCEG score recompute
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  22. 2026-06-13 04:21 UTCEG score recompute
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  25. 2026-06-12 16:17 UTCEG score recompute
  26. 2026-06-12 04:15 UTCEG score recompute
  27. 2026-06-11 16:50 UTCEG score recompute
  28. 2026-06-11 14:00 UTCEPSS rescore
  29. 2026-06-11 05:22 UTCEG score recompute
  30. 2026-06-10 22:18 UTCEPSS rescore
  31. 2026-06-10 17:56 UTCEG score recompute
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  34. 2026-06-10 06:32 UTCEG score recompute
  35. 2026-06-09 19:07 UTCEG score recompute
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  38. 2026-06-08 14:17 UTCEPSS rescore
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  40. 2026-06-08 08:53 UTCEG score recompute
  41. 2026-06-07 21:29 UTCEG score recompute
  42. 2026-06-07 15:25 UTCEPSS rescore
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  44. 2026-06-07 10:04 UTCEG score recompute
  45. 2026-06-06 22:40 UTCEG score recompute
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  48. 2026-06-06 11:16 UTCEG score recompute
  49. 2026-06-05 23:49 UTCEG score recompute
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  61. 2026-06-02 20:13 UTCEPSS rescore
  62. 2026-06-02 15:54 UTCEG score recompute
  63. 2026-06-02 04:29 UTCEG score recompute
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  65. 2026-06-01 13:52 UTCEPSS rescore
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  68. 2026-05-31 22:30 UTCEPSS rescore
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  72. 2026-05-29 13:44 UTCEPSS rescore
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  74. 2026-05-28 13:44 UTCEPSS rescore
  75. 2026-05-28 13:44 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-42327?
CVE-2026-42327 is a high vulnerability published on May 14, 2026. rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.7 to before 0.10.79, X509Ref::ocspresponders returns OCSP responder URLs from a certificate's AIA extension as OpensslString, whose Deref<Target = str> wraps the raw bytes with str::fromutf8_unchecked. OpenSSL does…
When was CVE-2026-42327 disclosed?
CVE-2026-42327 was first published in the National Vulnerability Database on May 14, 2026, with the most recent update on May 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42327 actively exploited?
CVE-2026-42327 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 11.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42327?
CVE-2026-42327 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-42327?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42327, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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