{"id":"CVE-2026-76844","title":"zlib 1.2.11 through 1.3.2 contains a heap buffer overflow: after an underlying write() fails, gz_write() returns without resetting strm.next_in, leaving it pointed at the caller's buffer","summary":"zlib 1.2.11 through 1.3.2 contains a heap buffer overflow: after an underlying write() fails, gz_write() returns without resetting strm.next_in, leaving it pointed at the caller's buffer. A later gz* write call then derives a position fr…","severity":"high","cvss":7.4,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","cwe":["CWE-787","CWE-22"],"vendor":"zlib","product":"zlib","affected":["zlib >= 1.2.11 <= 1.3.2"],"patched":["webpack-dev-middleware 8.3.0","webpack-dev-middleware 7.4.6"],"published":"2026-08-24","updated":"2026-10-12","sourceUpdated":"2026-10-12T17:10:00.163","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-76844","references":[{"url":"https://gist.github.com/thesmartshadow/e0b9481792afb7c31e86fee1ff084490","label":"disclosure@vulncheck.com"},{"url":"https://github.com/madler/zlib","label":"disclosure@vulncheck.com"},{"url":"https://github.com/madler/zlib/blob/v1.3.2/gzwrite.c#L393","label":"disclosure@vulncheck.com"},{"url":"https://github.com/madler/zlib/commit/df84af25dc1942490e1d1c899a07619152a46148","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/zlib-1.3.1.2-through-1.3.2-heap-buffer-overflow-via-gz-vacate","label":"disclosure@vulncheck.com"},{"url":"https://github.com/advisories/GHSA-wr3j-pwj9-hqq6","label":"disclosure@vulncheck.com"},{"url":"https://github.com/webpack/webpack-dev-middleware","label":"disclosure@vulncheck.com"},{"url":"https://github.com/webpack/webpack-dev-middleware/blob/v8.1.1/src/middleware.js","label":"disclosure@vulncheck.com"},{"url":"https://github.com/webpack/webpack-dev-middleware/commit/13344e78b26d88fe9b7c8381a3860e248a52359b","label":"disclosure@vulncheck.com"},{"url":"https://github.com/webpack/webpack-dev-middleware/commit/cefccbac330c29052fc6dffe85fd292ea2ac782b","label":"disclosure@vulncheck.com"},{"url":"https://github.com/webpack/webpack-dev-middleware/releases/tag/v7.4.6","label":"disclosure@vulncheck.com"},{"url":"https://github.com/webpack/webpack-dev-middleware/releases/tag/v8.3.0","label":"disclosure@vulncheck.com"},{"url":"https://github.com/webpack/webpack-dev-middleware/security/advisories/GHSA-g84c-rxfj-3j2c","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/webpack-dev-middleware-path-traversal-via-offset-slice-on-a-non-slash-terminated-publicpath","label":"disclosure@vulncheck.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-76844"},{"url":"https://github.com/webpack/webpack-dev-middleware/pull/2404"},{"url":"https://github.com/advisories/GHSA-g84c-rxfj-3j2c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76844.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-76844"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2521896"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-76844"},{"url":"https://access.redhat.com/errata/RHSA-2026:69296"},{"url":"https://access.redhat.com/errata/RHSA-2026:61783"},{"url":"https://access.redhat.com/errata/RHSA-2026:68681"}],"tags":["nvd","cve.org","exploit-available","ghsa","npm","csaf","vex","red-hat"],"epss":0.00592,"epssPercentile":0.48091,"aliases":["GHSA-g84c-rxfj-3j2c"],"ecosystem":"npm","exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-26T18:22:33.313523Z"},"scores":{"nvd":7.4,"vendor":8.6},"ingestedAt":"2026-09-24T20:51:40.221Z","slug":"CVE-2026-76844","body":"## Overview\n\nzlib 1.2.11 through 1.3.2 contains a heap buffer overflow: after an underlying write() fails, gz_write() returns without resetting strm.next_in, leaving it pointed at the caller's buffer. A later gz* write call then derives a position from the stale pointer and writes past a heap allocation; any write() failure reaches it, including EPIPE on a blocking descriptor, and in versions before 1.3.1.2 the failed write must be followed by a gzclearerr() call.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-76844)\n\nAffected packages:\n\n- `webpack-dev-middleware >= 8.0.0, < 8.3.0`\n- `webpack-dev-middleware < 7.4.5`\n\nPatched in:\n\n- `webpack-dev-middleware 8.3.0`\n- `webpack-dev-middleware 7.4.6`\n\nSource: https://github.com/advisories/GHSA-g84c-rxfj-3j2c\n\n## Vendor advisories\n\n- **RHSA-2026:69296** · Red Hat · fixed in: Red Hat Data Grid 8.6.3 · released 2026-09-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:69296)\n- **RHSA-2026:61783** · Red Hat · fixed in: Red Hat Discovery 2 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:61783)\n- **RHSA-2026:68681** · Red Hat · fixed in: Red Hat Migration Toolkit 1.8 · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68681)\n- **Red Hat VEX** · Important · affected: Node HealthCheck Operator, OpenShift Pipelines, Red Hat Ansible Automation Platform 2, Red Hat build of Apache Camel - HawtIO 4, Red Hat Build of Podman Desktop, Red Hat Ceph Storage 4, … · no fix planned: Red Hat Ansible Automation Platform 2, Red Hat build of Apache Camel - HawtIO 4, Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat Fuse 7, … · updated 2026-10-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76844.json)","depth":"midnight","depthScore":53,"depthScoreParts":{"impact":40.7,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":214230,"id":"CVE-2026-76844","ts":1790855008209,"field":"exploit_available","old":"false","new":"true"}]}