5.9

CVE-2026-42766: Possible NULL Dereference in Password-Based CMS Decryption

Analyzed
AliasesALPINE-CVE-2026-42766UBUNTU-CVE-2026-42766DEBIAN-CVE-2026-42766
Published 09-06-2026Last modified 10-06-2026

Vulnerability summary

CVE-2026-42766 is a medium (CVSS 5.9) NULL Pointer Dereference vulnerability in openssl. EPSS estimates a 1.06% chance of exploitation in the next 30 days, higher than 64.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.9, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
1.06%
0%100%
Low · -0.05 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 28 · Related 20
MGASA-2026-0253OPENSUSE-SU-2026:11023-1OPENSUSE-SU-2026:21005-1RHSA-2026:25237RHSA-2026:25239RHSA-2026:42825

Timeline

  1. 09-06-2026
    PublishedVulnerability first disclosed.
  2. 10-06-2026
    Last modifiedVulnerability information updated.

Description

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption. Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service. The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present. An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service. Applications that process password-encrypted CMS messages may be affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

1.06%

Chance of exploitation in the next 30 days

Percentile

65%

Versus all other CVEs

30-day change

Decrease -0.05 pp

From 1.11% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard15 products
  • eco-dotnet-libssl-1.0-ld-so-confAll versions (No fix recorded)
  • libcrypto3< 3.6.3-r0
  • libcrypto3-2.34< 3.6.3-r0
  • openssl< 3.6.3-r0
  • openssl-3.5< 3.5.7-r0
Ubuntu6 products
  • edk2All versions (No fix recorded)
  • edk2-hweAll versions (No fix recorded)
  • nodejsAll versions (No fix recorded)
  • openssl< 1.0.1f-1ubuntu2.27+esm14 | < 1.0.2g-1ubuntu4.20+esm16 | All versions (No fix recorded) | < 1.1.1-1ubuntu2.1~18.04.23+esm9 | < 1.1.1-1ubuntu2.fips.2.1~18.04.23.9 | < 1.1.1f-1ubuntu2.24+esm4 | < 1.1.1f-1ubuntu2.fips.24.4 | < 3.0.2-0ubuntu1.25 | < 3.0.2-0ubuntu1.25+Fips1 | < 3.0.13-0ubuntu3.11 | < 3.5.3-1ubuntu3.4 | < 3.5.5-1ubuntu3.2
  • openssl-fipsAll versions (No fix recorded) | < 3.0.13-0ubuntu3.12+Fips1
Wolfi5 products
  • libcrypto3< 3.6.3-r0
  • openssl< 3.6.3-r0
  • openssl-4.0< 4.0.1-r0
  • openssl-4.0-libcrypto< 4.0.1-r0
  • openssl-4.0-libssl< 4.0.1-r0
Alpine1 product
  • openssl≥ 1.0.2, < 3.3.7-r1 | ≥ 1.0.2, < 3.5.7-r0
Debian1 product
  • openssl< 3.0.20-1~deb12u2 | < 3.5.6-1~deb13u2 | < 3.6.3-1
Openssl1 product
  • openssl≥ 4.0.0, < 4.0.1 | ≥ 1.0.2, < 1.0.2zq | ≥ 1.1.1, < 1.1.1zh | ≥ 3.0.0, < 3.0.21 | ≥ 3.4.0, < 3.4.6 | ≥ 3.5.0, < 3.5.7 | ≥ 3.6.0, < 3.6.3 | 4.0.0

6 vendors · 29 products

References

14 links
Show all 14 references