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TI-2026-30633 Aliases CVE-2026-42327GHSA-xp3w-r5p5-63rr

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

Priority MEDIUM 43CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

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<Target = str> 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00211 11th percentileScored 2026-11-07
Fix Fixed rust-openssl (rust-openssl): 0.10.79openssl (crates.io): 0.10.79

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
rust-opensslrust-openssl0.9.7 to before 0.10.790.10.79Patch availableCNA
—openssl (crates.io)0.9.7 to before 0.10.790.10.79Patch availableGHSA-xp3w-r5p5-63rr
  • rust-openssl Vendorrust-openssl Affected 0.9.7 to before 0.10.79 Fixed in 0.10.79 Patch available CNA
  • openssl (crates.io) Vendor— Affected 0.9.7 to before 0.10.79 Fixed in 0.10.79 Patch available GHSA-xp3w-r5p5-63rr

Remediation

  • Fix · CNA rust-openssl (rust-openssl) Fixed in 0.10.79
  • Fix · GHSA-xp3w-r5p5-63rr openssl (crates.io) Fixed in 0.10.79 Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42327
  2. 2026-10-03 Alias added: GHSA-xp3w-r5p5-63rr

References

Advisory 1

Other 2

  • TI-2018-14959 An issue was discovered in the openssl crate before 0.10.9 for Rust. CVSS 3.0CRITICAL 9.8
  • TI-2026-30198 rust-openssl: MdCtxRef::digest_final() writes past caller buffer with no length check CVSS 4.0HIGH 8.1
  • TI-2026-30193 rust-openssl: Deriver::derive and PkeyCtxRef::derive can overflow short buffers on OpenSSL 1.1.1 CVSS 4.0HIGH 7.2
  • TI-2016-08969 An issue was discovered in the openssl crate before 0.9.0 for Rust. CVSS 3.0HIGH 8.1
  • TI-2026-30300 rust-openssl: Unchecked callback-returned length in PSK and cookie generate trampolines… CVSS 4.0HIGH 8.3
  • TI-2026-30195 rust-openssl: Incorrect bounds assertion in aes key wrap CVSS 4.0HIGH 7.2
See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences