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Advisory severityMedium6.5Vendor: LowRed Hat Linux

Medium [CVE-2026-42771] Possible Out of Bounds Read in X509_VERIFY_PARAM_set1_email

This medium-severity Red Hat Linux advisory covers CVE-2026-42771 affecting Red Hat Hardened Images, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-42771 Source published Source updated

VulniPulse record published Record updated

CVE-2026-42771
Affected products & platforms
Red Hat LinuxRed Hat Enterprise Linux
Open source advisory

Summary

Issue summary: When the X509_VERIFY_PARAM_set1_email is called by an application to validate a crafted e-mail address, such as during S/MIME message validation, an out of bounds read can happen. Impact summary: This out of bounds read will not directly exfiltrate the data read to the attacker so the most likely result is a crash and a Denial of Service.

An internal helper function called from X509_VERIFY_PARAM_[set|add]_email() used a wrong length when validating the local part of an email address. This could cause the 64 octet limit on the local part of an email address to be not enforced, or cause an out of bound read and potentially a crash.

The bug is reachable via S-MIME validation with a crafted From: address supplied in an email message that can potentially cause a crash. No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.

A flaw was found in OpenSSL. A remote attacker could exploit this vulnerability by sending a malicious email, leading to an application crash and a Denial of Service (DoS).

This flaw is rated as Low impact. A possible out-of-bounds read in OpenSSL's X509_VERIFY_PARAM_set1_email() function can occur when an application validates a specially crafted S/MIME email address.

Red Hat severity: Low — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H). Weakness: CWE-805.

Is CVE-2026-42771 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-42771 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-42771?

Upgrade to a fixed release named by Red Hat:

  • chunkah-main-0.6.0-3.hum1
  • python-cryptography-main-50.0.0-1.hum1
  • openssl3-main-3.5.8-0.1.hum1
  • openssl-main-3.5.8-0.1.hum1
  • ruby3-3-main-3.3.10-23.6.hum1
  • ruby4-0-main-4.0.6-37.3.hum1
  • ruby3-4-main-3.4.10-31.7.hum1
  • rust-bootupd-main-0.3.2-1.hum1
  • RHSA-2026:42825
  • RHSA-2026:55543
  • RHSA-2026:59635
  • RHSA-2026:59641

4 more fixed releases are listed below.

Confirm against the vendor advisory before you patch.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · high-confidence parse· fetched 5 days ago·verify at source

Fixed versions
  • chunkah-main-0.6.0-3.hum1
  • python-cryptography-main-50.0.0-1.hum1
  • openssl3-main-3.5.8-0.1.hum1
  • openssl-main-3.5.8-0.1.hum1
  • ruby3-3-main-3.3.10-23.6.hum1
  • ruby4-0-main-4.0.6-37.3.hum1
  • ruby3-4-main-3.4.10-31.7.hum1
  • rust-bootupd-main-0.3.2-1.hum1
  • RHSA-2026:42825
  • RHSA-2026:55543
  • RHSA-2026:59635
  • RHSA-2026:59641
  • RHSA-2026:62562
  • RHSA-2026:62563
  • RHSA-2026:62790
  • RHSA-2026:67551

Official advisory · high-confidence parse· fetched 5 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Official advisory · high-confidence parse· fetched 5 days ago·verify at source

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