A use-after-free and double-free vulnerability (CVE-2026-33630) in the c-ares DNS library's query-completion handling could allow an attacker to crash the service or potentially execute arbitrary code. The security impact is rated Important by Red Hat, but a specific CVSS score is not provided in this advisory. The update addresses the issue for Red Hat Enterprise Linux 10, with the fixed package version being c-ares-1.34.6-2.el10_2.
Red Hat Product Errata RHSA-2026:42096 - Security Advisory Issued: 2026-07-20 Updated: 2026-07-20 RHSA-2026:42096 - Security Advisory Overview Updated Packages Synopsis Important: c-ares security update Type/Severity Security Advisory: Important Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for c-ares is now available for Red Hat Enterprise Linux 10. 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 c-ares C library defines asynchronous DNS (Domain Name System) requests and provides name resolving API. Security Fix(es): c-ares: c-ares: Use-after-free / double-free in query-completion handling (CVE-2026-33630) 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 10 x86_64 Red Hat Enterprise Linux for x86_64 - Extended Update Support 10.2 x86_64 Red Hat Enterprise Linux for IBM z Systems 10 s390x Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.2 s390x Red Hat Enterprise Linux for Power, little endian 10 ppc64le Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.2 ppc64le Red Hat Enterprise Linux for ARM 64 10 aarch64 Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.2 aarch64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.2 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.2 s390x Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.2 ppc64le Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.2 x86_64 Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 10.2 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 10.2 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 10.2 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 10.2 s390x Fixes BZ - 2497686 - CVE-2026-33630 c-ares: c-ares: Use-after-free / double-free in query-completion handling CVEs CVE-2026-33630 References https://access.redhat.com/security/updates/classification/#important Note: More recent versions of these packages may be available. Click a package name for more details. Red Hat Enterprise Linux for x86_64 10 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 x86_64 c-ares-1.34.6-2.el10_2.x86_64.rpm SHA-256: 4d973e180e78f109489e33534a1121f4315edf70e0ed3fe75779dca1786f763e c-ares-debuginfo-1.34.6-2.el10_2.x86_64.rpm SHA-256: 8709b2e80a52e668bc479073a5df948f21769998257c063a62fb176dd348f416 c-ares-debuginfo-1.34.6-2.el10_2.x86_64.rpm SHA-256: 8709b2e80a52e668bc479073a5df948f21769998257c063a62fb176dd348f416 c-ares-debugsource-1.34.6-2.el10_2.x86_64.rpm SHA-256: bdcf9fe1e849158196b7530ed230b8c1079adecff7fd2e9f44a7ad9cd0e7d77f c-ares-debugsource-1.34.6-2.el10_2.x86_64.rpm SHA-256: bdcf9fe1e849158196b7530ed230b8c1079adecff7fd2e9f44a7ad9cd0e7d77f c-ares-devel-1.34.6-2.el10_2.x86_64.rpm SHA-256: 2da1b1e200a2eb5d3529c73c8a6de49ee0bf529006ad2088e443741db05ec6ec Red Hat Enterprise Linux for x86_64 - Extended Update Support 10.2 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 x86_64 c-ares-1.34.6-2.el10_2.x86_64.rpm SHA-256: 4d973e180e78f109489e33534a1121f4315edf70e0ed3fe75779dca1786f763e c-ares-debuginfo-1.34.6-2.el10_2.x86_64.rpm SHA-256: 8709b2e80a52e668bc479073a5df948f21769998257c063a62fb176dd348f416 c-ares-debuginfo-1.34.6-2.el10_2.x86_64.rpm SHA-256: 8709b2e80a52e668bc479073a5df948f21769998257c063a62fb176dd348f416 c-ares-debugsource-1.34.6-2.el10_2.x86_64.rpm SHA-256: bdcf9fe1e849158196b7530ed230b8c1079adecff7fd2e9f44a7ad9cd0e7d77f c-ares-debugsource-1.34.6-2.el10_2.x86_64.rpm SHA-256: bdcf9fe1e849158196b7530ed230b8c1079adecff7fd2e9f44a7ad9cd0e7d77f c-ares-devel-1.34.6-2.el10_2.x86_64.rpm SHA-256: 2da1b1e200a2eb5d3529c73c8a6de49ee0bf529006ad2088e443741db05ec6ec Red Hat Enterprise Linux for IBM z Systems 10 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 s390x c-ares-1.34.6-2.el10_2.s390x.rpm SHA-256: 837c86b8a9cddce89d789ec21d1e30636062e2fad820a67c3517f39c334e6fd5 c-ares-debuginfo-1.34.6-2.el10_2.s390x.rpm SHA-256: 0673d801125933c312f95287732074c84673750f8e6727c24105a473660f00e3 c-ares-debuginfo-1.34.6-2.el10_2.s390x.rpm SHA-256: 0673d801125933c312f95287732074c84673750f8e6727c24105a473660f00e3 c-ares-debugsource-1.34.6-2.el10_2.s390x.rpm SHA-256: 94031c5200305fc9af01466b94d88a46ea01c7b57a23071f85ecfbb5b01e8aa2 c-ares-debugsource-1.34.6-2.el10_2.s390x.rpm SHA-256: 94031c5200305fc9af01466b94d88a46ea01c7b57a23071f85ecfbb5b01e8aa2 c-ares-devel-1.34.6-2.el10_2.s390x.rpm SHA-256: 3c198a3f3af71a01531af05c9a7108034bbda2c5195b001c5de9a7060369ab3e Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.2 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 s390x c-ares-1.34.6-2.el10_2.s390x.rpm SHA-256: 837c86b8a9cddce89d789ec21d1e30636062e2fad820a67c3517f39c334e6fd5 c-ares-debuginfo-1.34.6-2.el10_2.s390x.rpm SHA-256: 0673d801125933c312f95287732074c84673750f8e6727c24105a473660f00e3 c-ares-debuginfo-1.34.6-2.el10_2.s390x.rpm SHA-256: 0673d801125933c312f95287732074c84673750f8e6727c24105a473660f00e3 c-ares-debugsource-1.34.6-2.el10_2.s390x.rpm SHA-256: 94031c5200305fc9af01466b94d88a46ea01c7b57a23071f85ecfbb5b01e8aa2 c-ares-debugsource-1.34.6-2.el10_2.s390x.rpm SHA-256: 94031c5200305fc9af01466b94d88a46ea01c7b57a23071f85ecfbb5b01e8aa2 c-ares-devel-1.34.6-2.el10_2.s390x.rpm SHA-256: 3c198a3f3af71a01531af05c9a7108034bbda2c5195b001c5de9a7060369ab3e Red Hat Enterprise Linux for Power, little endian 10 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 ppc64le c-ares-1.34.6-2.el10_2.ppc64le.rpm SHA-256: dcc75a3716408faa7cb49bf5753b60ba283b53da939a34d31e363bcc04b70389 c-ares-debuginfo-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e6e6f6f2448db279777d2e5f28cb5d86d1a1b71c7832f210019102812859f797 c-ares-debuginfo-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e6e6f6f2448db279777d2e5f28cb5d86d1a1b71c7832f210019102812859f797 c-ares-debugsource-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e87a0cbc56323e07ee6ceaedde248babb27d511fad11a013aaa31a60488d1cf6 c-ares-debugsource-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e87a0cbc56323e07ee6ceaedde248babb27d511fad11a013aaa31a60488d1cf6 c-ares-devel-1.34.6-2.el10_2.ppc64le.rpm SHA-256: fbbc9669b34ce57d9f5280378e787f8f2421073a412b9f7ff5716c9b4a17b3c6 Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.2 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 ppc64le c-ares-1.34.6-2.el10_2.ppc64le.rpm SHA-256: dcc75a3716408faa7cb49bf5753b60ba283b53da939a34d31e363bcc04b70389 c-ares-debuginfo-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e6e6f6f2448db279777d2e5f28cb5d86d1a1b71c7832f210019102812859f797 c-ares-debuginfo-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e6e6f6f2448db279777d2e5f28cb5d86d1a1b71c7832f210019102812859f797 c-ares-debugsource-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e87a0cbc56323e07ee6ceaedde248babb27d511fad11a013aaa31a60488d1cf6 c-ares-debugsource-1.34.6-2.el10_2.ppc64le.rpm SHA-256: e87a0cbc56323e07ee6ceaedde248babb27d511fad11a013aaa31a60488d1cf6 c-ares-devel-1.34.6-2.el10_2.ppc64le.rpm SHA-256: fbbc9669b34ce57d9f5280378e787f8f2421073a412b9f7ff5716c9b4a17b3c6 Red Hat Enterprise Linux for ARM 64 10 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 aarch64 c-ares-1.34.6-2.el10_2.aarch64.rpm SHA-256: 07299e2ad9e153adb2b0fd8d491760535141f4bbdee9fd77be6f8ca803da120a c-ares-debuginfo-1.34.6-2.el10_2.aarch64.rpm SHA-256: bddbe9acf946601ea1cefbe6fbe7b58d1f09e1b538f2df7e1007f208c10a157c c-ares-debuginfo-1.34.6-2.el10_2.aarch64.rpm SHA-256: bddbe9acf946601ea1cefbe6fbe7b58d1f09e1b538f2df7e1007f208c10a157c c-ares-debugsource-1.34.6-2.el10_2.aarch64.rpm SHA-256: a5bf08ab0bf89d5f0895a2a44f3748b28f94540824f6991c42f49ea824046060 c-ares-debugsource-1.34.6-2.el10_2.aarch64.rpm SHA-256: a5bf08ab0bf89d5f0895a2a44f3748b28f94540824f6991c42f49ea824046060 c-ares-devel-1.34.6-2.el10_2.aarch64.rpm SHA-256: 27a9f1264e50aeefb20230343b851e887a74eb9e72295f234eb2726582b93f49 Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.2 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 aarch64 c-ares-1.34.6-2.el10_2.aarch64.rpm SHA-256: 07299e2ad9e153adb2b0fd8d491760535141f4bbdee9fd77be6f8ca803da120a c-ares-debuginfo-1.34.6-2.el10_2.aarch64.rpm SHA-256: bddbe9acf946601ea1cefbe6fbe7b58d1f09e1b538f2df7e1007f208c10a157c c-ares-debuginfo-1.34.6-2.el10_2.aarch64.rpm SHA-256: bddbe9acf946601ea1cefbe6fbe7b58d1f09e1b538f2df7e1007f208c10a157c c-ares-debugsource-1.34.6-2.el10_2.aarch64.rpm SHA-256: a5bf08ab0bf89d5f0895a2a44f3748b28f94540824f6991c42f49ea824046060 c-ares-debugsource-1.34.6-2.el10_2.aarch64.rpm SHA-256: a5bf08ab0bf89d5f0895a2a44f3748b28f94540824f6991c42f49ea824046060 c-ares-devel-1.34.6-2.el10_2.aarch64.rpm SHA-256: 27a9f1264e50aeefb20230343b851e887a74eb9e72295f234eb2726582b93f49 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.2 SRPM c-ares-1.34.6-2.el10_2.src.rpm SHA-256: c2432f6df7014e0d2b3c43c7f313cca3fb7f8ae6aace5fe0dce6903df9af2971 aarch64 c-ares-1.34.6-2.el10_2.aarch64.rpm SHA-256: 07299e2ad9e153adb2b0fd8d491760535141f4bb