--- id: "CVE-2023-4911" kind: "vulnerability" aliases: ["CVE-2023-4911"] title: "A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES\u2026" severity: "high" cvss: 7.8 epss: null exploited: true status: "open" category: "infrastructure" products: [{"name": "GNU GNU C Library", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "netapp bootstrap os", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "siemens simatic s7-1500 cpu 1518-4 pn\\/dp mfp firmware", "fixed": [], "affected": ">= 3.1.5", "ecosystem": "vendor"}, {"name": "siemens simatic s7-1500 cpu 1518f-4 pn\\/dp mfp firmware", "fixed": [], "affected": ">= 3.1.5", "ecosystem": "vendor"}, {"name": "siemens siplus s7-1500 cpu 1518-4 pn\\/dp mfp firmware", "fixed": [], "affected": ">= 3.1.5", "ecosystem": "vendor"}, {"name": "siemens simatic s7-1500 tm mfp firmware", "fixed": ["1.1"], "affected": "< 1.1", "ecosystem": "vendor"}, {"name": "gnu glibc", "fixed": ["2.39"], "affected": ">= 2.34, < 2.39", "ecosystem": "vendor"}, {"name": "fedoraproject fedora", "fixed": [], "affected": "= 37", "ecosystem": "vendor"}, {"name": "fedoraproject fedora", "fixed": [], "affected": "= 38", "ecosystem": "vendor"}, {"name": "fedoraproject fedora", "fixed": [], "affected": "= 39", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder", "fixed": [], "affected": "= 9.0", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder eus", "fixed": [], "affected": "= 8.6", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder eus", "fixed": [], "affected": "= 9.2", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder eus", "fixed": [], "affected": "= 9.4", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder eus", "fixed": [], "affected": "= 9.6", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for arm64", "fixed": [], "affected": "= 9.0_aarch64", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for arm64 eus", "fixed": [], "affected": "= 8.6", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for arm64 eus", "fixed": [], "affected": "= 9.2_aarch64", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for arm64 eus", "fixed": [], "affected": "= 9.4_aarch64", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for arm64 eus", "fixed": [], "affected": "= 9.6_aarch64", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for ibm z systems", "fixed": [], "affected": "= 9.0_s390x", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for ibm z systems eus", "fixed": [], "affected": "= 8.6", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for ibm z systems eus", "fixed": [], "affected": "= 9.2_s390x", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for ibm z systems eus", "fixed": [], "affected": "= 9.4_s390x", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for ibm z systems eus", "fixed": [], "affected": "= 9.6_s390x", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for power little endian", "fixed": [], "affected": "= 9.0_ppc64le", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for power little endian eus", "fixed": [], "affected": "= 8.6", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for power little endian eus", "fixed": [], "affected": "= 9.2_ppc64le", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for power little endian eus", "fixed": [], "affected": "= 9.4_ppc64le", "ecosystem": "vendor"}, {"name": "redhat codeready linux builder for power little endian eus", "fixed": [], "affected": "= 9.6_ppc64le", "ecosystem": "vendor"}, {"name": "redhat virtualization", "fixed": [], "affected": "= 4.0", "ecosystem": "vendor"}, {"name": "redhat virtualization host", "fixed": [], "affected": "= 4.0", "ecosystem": "vendor"}, {"name": "redhat enterprise linux", "fixed": [], "affected": "= 8.0", "ecosystem": "vendor"}, {"name": "redhat enterprise linux", "fixed": [], "affected": "= 9.0", "ecosystem": "vendor"}, {"name": "redhat enterprise linux eus", "fixed": [], "affected": "= 8.6", "ecosystem": "vendor"}, {"name": "redhat enterprise linux eus", "fixed": [], "affected": "= 9.2", "ecosystem": "vendor"}, {"name": "redhat enterprise linux eus", "fixed": [], "affected": "= 9.4", "ecosystem": "vendor"}, {"name": "redhat enterprise linux eus", "fixed": [], "affected": "= 9.6", "ecosystem": "vendor"}, {"name": "redhat enterprise linux for arm 64", "fixed": [], "affected": "= 9.0_aarch64", "ecosystem": "vendor"}, {"name": "redhat enterprise linux for arm 64 eus", "fixed": [], "affected": "= 8.6_aarch64", "ecosystem": "vendor"}, {"name": "redhat enterprise linux for arm 64 eus", "fixed": [], "affected": "= 9.2_aarch64", "ecosystem": "vendor"}] ecosystems: ["vendor"] tags: ["exploited", "glibc", "infrastructure", "linux", "self-hosted", "shared-hosts"] not_affected_if: ["managed-hosting-patched", "non-vulnerable-glibc-version"] published_at: "2023-10-03T18:15:10+00:00" first_seen_at: "2026-10-23T19:11:51+00:00" updated_at: "2026-10-23T22:29:04+00:00" sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-4911", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-4911", "first_seen_at": "2026-10-23T22:29:04+00:00"}] --- # A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES… The GNU C Library dynamic loader (ld.so) has a buffer overflow when it parses the GLIBC_TUNABLES environment variable. A local attacker can run code with elevated privileges, typically root, by setting that variable. _Summary, check and fix written by a model from the sources; labelled as such._ ## Affected - vendor:GNU GNU C Library affected ? fixed ? - vendor:netapp bootstrap os affected ? fixed ? - vendor:siemens simatic s7-1500 cpu 1518-4 pn\/dp mfp firmware affected >= 3.1.5 fixed ? - vendor:siemens simatic s7-1500 cpu 1518f-4 pn\/dp mfp firmware affected >= 3.1.5 fixed ? - vendor:siemens siplus s7-1500 cpu 1518-4 pn\/dp mfp firmware affected >= 3.1.5 fixed ? - vendor:siemens simatic s7-1500 tm mfp firmware affected < 1.1 fixed 1.1 - vendor:gnu glibc affected >= 2.34, < 2.39 fixed 2.39 - vendor:fedoraproject fedora affected = 37 fixed ? - vendor:fedoraproject fedora affected = 38 fixed ? - vendor:fedoraproject fedora affected = 39 fixed ? - vendor:redhat codeready linux builder affected = 9.0 fixed ? - vendor:redhat codeready linux builder eus affected = 8.6 fixed ? - vendor:redhat codeready linux builder eus affected = 9.2 fixed ? - vendor:redhat codeready linux builder eus affected = 9.4 fixed ? - vendor:redhat codeready linux builder eus affected = 9.6 fixed ? - vendor:redhat codeready linux builder for arm64 affected = 9.0_aarch64 fixed ? - vendor:redhat codeready linux builder for arm64 eus affected = 8.6 fixed ? - vendor:redhat codeready linux builder for arm64 eus affected = 9.2_aarch64 fixed ? - vendor:redhat codeready linux builder for arm64 eus affected = 9.4_aarch64 fixed ? - vendor:redhat codeready linux builder for arm64 eus affected = 9.6_aarch64 fixed ? - vendor:redhat codeready linux builder for ibm z systems affected = 9.0_s390x fixed ? - vendor:redhat codeready linux builder for ibm z systems eus affected = 8.6 fixed ? - vendor:redhat codeready linux builder for ibm z systems eus affected = 9.2_s390x fixed ? - vendor:redhat codeready linux builder for ibm z systems eus affected = 9.4_s390x fixed ? - vendor:redhat codeready linux builder for ibm z systems eus affected = 9.6_s390x fixed ? - vendor:redhat codeready linux builder for power little endian affected = 9.0_ppc64le fixed ? - vendor:redhat codeready linux builder for power little endian eus affected = 8.6 fixed ? - vendor:redhat codeready linux builder for power little endian eus affected = 9.2_ppc64le fixed ? - vendor:redhat codeready linux builder for power little endian eus affected = 9.4_ppc64le fixed ? - vendor:redhat codeready linux builder for power little endian eus affected = 9.6_ppc64le fixed ? - vendor:redhat virtualization affected = 4.0 fixed ? - vendor:redhat virtualization host affected = 4.0 fixed ? - vendor:redhat enterprise linux affected = 8.0 fixed ? - vendor:redhat enterprise linux affected = 9.0 fixed ? - vendor:redhat enterprise linux eus affected = 8.6 fixed ? - vendor:redhat enterprise linux eus affected = 9.2 fixed ? - vendor:redhat enterprise linux eus affected = 9.4 fixed ? - vendor:redhat enterprise linux eus affected = 9.6 fixed ? - vendor:redhat enterprise linux for arm 64 affected = 9.0_aarch64 fixed ? - vendor:redhat enterprise linux for arm 64 eus affected = 8.6_aarch64 fixed ? - vendor:redhat enterprise linux for arm 64 eus affected = 9.2_aarch64 fixed ? ## How to check Run ldd --version to see the glibc version and compare it to the fixed release in your distro's advisory. ## Fix Update the glibc package from your OS vendor to the patched build for CVE-2023-4911. ## Timeline - 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-4911 - 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2023-4911 ## From the sources GNU C Library's dynamic loader ld.so contains a buffer overflow vulnerability when processing the GLIBC_TUNABLES environment variable, allowing a local attacker to execute code with elevated privileges. CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. --- _Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_