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Fencer Vulns
high 8.7

CVE-2026-42327 json

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

published 2026-05-05 6 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-30474 , GHSA-xp3w-r5p5-63rr

cvss
8.7
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

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.

Patch / fix

  • crates.io openssl 0.10.79
  • rust-openssl_project rust-openssl 0.10.79
  • rust-openssl Debian 14 0.10.79-1

debian advisories DEBIAN-CVE-2026-42327

  • rustup SLES for SAP applications 16.0, SLES 16.0 1.29.1~0-160000.1.1
  • sccache SLES for SAP applications 16.0, SLES 16.0 0.18.0~2-160000.1.1
  • snpguest SLE Module for Server Applications 15 SP7 0.10.0-150700.3.6.1
  • snphost SLES for SAP applications 16.0, SLES 16.0 0.6.0-160000.3.1
  • snphost SLE Module for Confidential Computing Technical Preview 15 SP7 0.6.1-150700.3.6.1
  • snpguest SLES for SAP applications 16.0, SLES 16.0 0.10.0-160000.2.1
  • himmelblau SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES 15 SP6-LTSS +3 more 2.3.14+git0.e23b4c54-150500.11.12.1
  • afterburn Linux Micro 6.1 5.10.0.git73.b97f772-slfo.1.1_1.1

suse advisories SUSE-SU-2026:24014-1SUSE-SU-2026:23983-1SUSE-SU-2026:3791-1SUSE-SU-2026:23327-1SUSE-SU-2026:3642-1SUSE-SU-2026:23236-1

  • rustup openSUSE Leap 16.0 1.29.1~0-160000.1.1
  • sccache openSUSE Leap 16.0 0.18.0~2-160000.1.1
  • sdbootutil openSUSE Leap 16.0 1+git20260908.c641fc2-160000.1.1
  • snpguest openSUSE Tumbleweed 0.10.0-3.1
  • snphost openSUSE Tumbleweed 0.7.0-3.1
  • snphost openSUSE Leap 16.0 0.6.0-160000.3.1
  • snpguest openSUSE Leap 16.0 0.10.0-160000.2.1
  • libkrun openSUSE Leap 16.0 1.4.10-160000.3.1

opensuse advisories openSUSE-SU-2026:22016-1openSUSE-SU-2026:21982-1openSUSE-SU-2026:21933-1openSUSE-SU-2026:11653-1openSUSE-SU-2026:11654-1openSUSE-SU-2026:21638-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42327 updated cvss 9.1

rust-openssl: rust-openssl: Arbitrary code execution via specially crafted certificate

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
crates.io openssl
>=0.9.7, <0.10.79
0.10.79

Affected products

  • rust-openssl rust-openssl

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.