RHSA-2026:26409 - Security Advisory

Topic

An update for gnutls is now available for Red Hat Enterprise Linux 10.0 Extended Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The gnutls packages provide the GNU Transport Layer Security (GnuTLS) library, which implements cryptographic algorithms and protocols such as SSL, TLS, and DTLS.

Security Fix(es):

• gnutls: gnutls: Security bypass allows acceptance of revoked server certificates via crafted OCSP response (CVE-2026-3832)
• gnutls: GnuTLS: Policy bypass due to case-sensitive nameConstraints comparison (CVE-2026-3833)
• gnutls: GnuTLS: Denial of Service via DTLS zero-length fragment (CVE-2026-33845)
• gnutls: GnuTLS: Denial of Service via heap buffer overflow in DTLS handshake fragment reassembly (CVE-2026-33846)
• gnutls: Fix qsort comparator in DTLS reassembly (CVE-2026-42009)
• gnutls: gnutls: Authentication Bypass via NUL Character in Username (CVE-2026-42010)
• gnutls: gnutls: Security bypass due to incorrect name constraint handling (CVE-2026-42011)
• gnutls: gnutls: Certificate validation bypass due to improper handling of URI and SRV SANs (CVE-2026-42012)
• gnutls: gnutls: Certificate validation bypass due to oversized Subject Alternative Name (CVE-2026-42013)
• gnutls: gnutls: Information disclosure via heap overread in RSA key exchange (CVE-2026-5260)
• gnutls: Fix use-after-free in gnutls_pkcs11_token_set_pin (CVE-2026-42014)
• gnutls: gnutls: Memory corruption due to off-by-one error in PKCS#12 bag handling (CVE-2026-42015)
• guntls: gnutls: Information disclosure via timing side-channel in PKCS#7 padding removal (CVE-2026-5419)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 10.0 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.0 s390x
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.0 ppc64le
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.0 aarch64
• Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.0 aarch64
• Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.0 s390x
• Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.0 ppc64le
• Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.0 x86_64

Fixes

• BZ - 2445762 - CVE-2026-3832 gnutls: gnutls: Security bypass allows acceptance of revoked server certificates via crafted OCSP response
• BZ - 2445763 - CVE-2026-3833 gnutls: GnuTLS: Policy bypass due to case-sensitive nameConstraints comparison
• BZ - 2450624 - CVE-2026-33845 gnutls: GnuTLS: Denial of Service via DTLS zero-length fragment
• BZ - 2450625 - CVE-2026-33846 gnutls: GnuTLS: Denial of Service via heap buffer overflow in DTLS handshake fragment reassembly
• BZ - 2467279 - CVE-2026-42009 gnutls: gnutls: Denial of Service via DTLS packet reordering vulnerability
• BZ - 2467289 - CVE-2026-42010 gnutls: gnutls: Authentication Bypass via NUL Character in Username
• BZ - 2467437 - CVE-2026-42011 gnutls: gnutls: Security bypass due to incorrect name constraint handling
• BZ - 2467441 - CVE-2026-42012 gnutls: gnutls: Certificate validation bypass due to improper handling of URI and SRV SANs
• BZ - 2467448 - CVE-2026-42013 gnutls: gnutls: Certificate validation bypass due to oversized Subject Alternative Name
• BZ - 2467450 - CVE-2026-5260 gnutls: gnutls: Information disclosure via heap overread in RSA key exchange
• BZ - 2467451 - CVE-2026-42014 gnutls: Fix use-after-free in gnutls_pkcs11_token_set_pin
• BZ - 2467678 - CVE-2026-42015 gnutls: gnutls: Memory corruption due to off-by-one error in PKCS#12 bag handling
• BZ - 2467686 - CVE-2026-5419 guntls: gnutls: Information disclosure via timing side-channel in PKCS#7 padding removal

CVEs

• CVE-2026-3832
• CVE-2026-3833
• CVE-2026-5260
• CVE-2026-5419
• CVE-2026-33845
• CVE-2026-33846
• CVE-2026-42009
• CVE-2026-42010
• CVE-2026-42011
• CVE-2026-42012
• CVE-2026-42013
• CVE-2026-42014
• CVE-2026-42015

References

• https://access.redhat.com/security/updates/classification/#important