{"id":"CVE-2026-23455","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","cwe":["CWE-125"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 2.6.17, < 5.10.253","linux_kernel >= 5.11, < 5.15.203","linux_kernel >= 5.16, < 6.1.167","linux_kernel >= 6.2, < 6.6.130","linux_kernel >= 6.7, < 6.12.78","linux_kernel >= 6.13, < 6.18.20","linux_kernel >= 6.19, < 6.19.10","linux_kernel = 7.0"],"patched":["linux_kernel 6.19.10"],"published":"2026-04-03","updated":"2026-07-24","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-23455","references":[{"url":"https://git.kernel.org/stable/c/2121f5fbe88daff0f1fc5bc47d359426c74b86b0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/495e97af9e7249ee02b72bb1d0848a6efc3700f4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/633e8f87dad32263f6a57dccdb873f042c062111","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/65fa92f79677858b14b9e4b7275f26639afe2710","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9d00fe7d6d7c5b5f1065a6e042b54f2e44bd6df8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b652b05d51003ac074b912684f9ec7486231717b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f173d0f4c0f689173f8cdac79991043a4a89bf66","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f5e4f4e4cdb75ec36802059a94195a31f193da60","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.01338,"epssPercentile":0.70043,"ingestedAt":"2026-07-25T22:05:03.375Z","slug":"CVE-2026-23455","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it by 1 to skip the protocol discriminator\nbyte before passing it to DecodeH323_UserInformation(). If the encoded\nlength is 0, the decrement wraps to -1, which is then passed as a\nlarge value to the decoder, leading to an out-of-bounds read.\n\nAdd a check to ensure len is positive after the decrement.\n\n## Affected\n\n- `linux_kernel >= 2.6.17, < 5.10.253`\n- `linux_kernel >= 5.11, < 5.15.203`\n- `linux_kernel >= 5.16, < 6.1.167`\n- `linux_kernel >= 6.2, < 6.6.130`\n- `linux_kernel >= 6.7, < 6.12.78`\n- `linux_kernel >= 6.13, < 6.18.20`\n- `linux_kernel >= 6.19, < 6.19.10`\n- `linux_kernel = 7.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.19.10`","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.3,"exploitation":0,"ransomware":0},"changes":[]}