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ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr() There exists a kernel oops caused by a BUG_ON(nhead < 0) at net/core/skbuff.c:2232 in pskb_expand_head(). This bug is triggered as part of the calipso_skbuff_setattr() routine when skb_cow() is passed headroom > INT_MAX (i.e. (int)(skb_headroom(skb) + len_delta) < 0). The root cause of the bug is due to an implicit integer cast in __skb_cow(). The check (headroom > skb_headroom(skb)) is meant to ensure that delta = headroom - skb_headroom(skb) is never negative, otherwise we will trigger a BUG_ON in pskb_expand_head(). However, if headroom > INT_MAX and delta <= -NET_SKB_PAD, the check passes, delta becomes negative, and pskb_expand_head() is passed a negative value for nhead. Fix the trigger condition in calipso_skbuff_setattr(). Avoid passing "negative" headroom sizes to skb_cow() within calipso_skbuff_setattr() by only using skb_cow() to grow headroom. PoC: Using `netlabelctl` tool: netlabelctl map del default netlabelctl calipso add pass doi:7 netlabelctl map add default address:0::1/128 protocol:calipso,7 Then run the following PoC: int fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP); // setup msghdr int cmsg_size = 2; int cmsg_len = 0x60; struct msghdr msg; struct sockaddr_in6 dest_addr; struct cmsghdr * cmsg = (struct cmsghdr *) calloc(1, sizeof(struct cmsghdr) + cmsg_len); msg.msg_name = &dest_addr; msg.msg_namelen = sizeof(dest_addr

Announced Source revision 1
Original source ↗

CVE-2025-71085

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2025-71085

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
        "lessThan": "86f365897068d09418488165a68b23cb5baa37f2",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
        "lessThan": "6b7522424529556c9cbc15e15e7bd4eeae310910",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
        "lessThan": "2bb759062efa188ea5d07242a43e5aa5464bbae1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
        "lessThan": "c53aa6a5086f03f19564096ee084a202a8c738c0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
        "lessThan": "bf3709738d8a8cc6fa275773170c5c29511a0b24",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
        "lessThan": "73744ad5696dce0e0f43872aba8de6a83d6ad570",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
        "lessThan": "58fc7342b529803d3c221101102fe913df7adb83",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/ipv6/calipso.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.8"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.8",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.248",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.198",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.120",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.64",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.4",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/ipv6/calipso.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2025-71085

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#39143 · Revision 1
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Publisher date
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