8.7

CVE-2026-42327: rust-openssl Improper Input Validation

CVSS: 8.7v4.0HighDeferred
AliasesUBUNTU-CVE-2026-42327DEBIAN-CVE-2026-42327CGA-3r2j-v633-4fw2
Published 14-05-2026Last modified 15-05-2026
Open JSON

Vulnerability summary

CVE-2026-42327 is a high (CVSS 8.7) Improper Input Validation vulnerability in rust-openssl. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.6% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.21%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 61 · Related 62
OPENSUSE-SU-2026:11210-1OPENSUSE-SU-2026:11222-1OPENSUSE-SU-2026:11223-1OPENSUSE-SU-2026:11224-1OPENSUSE-SU-2026:11237-1OPENSUSE-SU-2026:11255-1

Timeline

  1. 14-05-2026
    PublishedVulnerability first disclosed.
  2. 15-05-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

11%

Versus all other CVEs

30-day change

0.00 pp

From 0.21% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.21%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard20 products
  • bootc-binary< 1.15.2-r1
  • deno< 2.7.14-r2
  • guestproxyagent< 1.0.44-r0
  • komodo-cli< 2.1.2-r3
  • komodo-periphery< 2.1.2-r3
Wolfi8 products
  • deno< 2.7.14-r2
  • rpm-sequoia< 1.10.2-r1
  • rustup< 1.29.0-r7
  • sccache< 0.15.0-r2
  • sdp-identity-service< 1.3.10-r7
Crates.Io1 product
  • openssl≥ 0.9.7, < 0.10.79
Debian1 product
  • rust-opensslAll versions (No fix recorded) | < 0.10.79-1
Rust-openssl1 product
Ubuntu1 product
  • rust-opensslAll versions (No fix recorded)

6 vendors · 32 products

References

7 links