> CVE-2025-71085

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PUBLISHED
2026-01-13 16:16
MODIFIED
2026-01-13 16:16
EPSS (Prob. Exploit)
0.31%
Top 77.8%
DATA SOURCES:
NVD 🔗 2026-01-13 RED HAT 🔗 2026-01-18 CVE PROJECT 🔗 2026-01-19 FIRST EPSS 🔗 2026-10-25 OSV 🔗 2026-01-19

> DESCRIPTION

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); msg.msg_iov = NULL; msg.msg_iovlen = 0; msg.msg_control = cmsg; msg.msg_controllen = cmsg_len; msg.msg_flags = 0; // setup sockaddr dest_addr.sin6_family = AF_INET6; dest_addr.sin6_port = htons(31337); dest_addr.sin6_flowinfo = htonl(31337); dest_addr.sin6_addr = in6addr_loopback; dest_addr.sin6_scope_id = 31337; // setup cmsghdr cmsg->cmsg_len = cmsg_len; cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_HOPOPTS; char * hop_hdr = (char *)cmsg + sizeof(struct cmsghdr); hop_hdr[1] = 0x9; //set hop size - (0x9 + 1) * 8 = 80 sendmsg(fd, &msg, 0);

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CV...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CV...
Red Hat Security Advisory: kernel-rt security update
An update for kernel-rt is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (C...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 9.4 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulner...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulner...
Red Hat Security Advisory: kernel-rt security update
An update for kernel-rt is now available for Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Moderate. A...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 8.2 Advanced Update Support. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulner...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions, and Red Hat Enterprise...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service. Red Hat Product Security h...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Moderate. A Com...
Red Hat Security Advisory: kernel-rt security update
An update for kernel-rt is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Moderate. A...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Moderate. A Com...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 10.0 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulne...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On. Red Hat Prod...

> RED HAT SEVERITY ASSESSMENT

THREAT SEVERITY
Moderate

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

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

AFFECTED PACKAGES:
Unknown / Unknown
796 versions affected
Linux / Kernel

> HISTORIQUE DES MODIFICATIONS

Première apparition
13/01/2026 16:16
Source: NVD
📊 ENRICHISSEMENT 19/01/2026 17:39
CVEPROJECT
Champ modifié: CVE Project
Ancienne valeur:
Non
Nouvelle valeur:
Oui
📊 ENRICHISSEMENT 18/01/2026 05:01
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 23:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 22:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 21:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 20:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 19:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 18:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 17:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 16:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 15:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 14:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 13:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Moderate" }
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 12:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
N/A
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 14/01/2026 12:30
REDHAT
Champ modifié: Red Hat
Ancienne valeur:
Non
Nouvelle valeur:
Oui
Total des modifications: 15 Dernière mise à jour: 9 months ago

> REFERENCES

https://git.kernel.org/stable/c/2bb759062efa188ea5d07242a43e5aa5464bbae1
https://git.kernel.org/stable/c/58fc7342b529803d3c221101102fe913df7adb83
https://git.kernel.org/stable/c/73744ad5696dce0e0f43872aba8de6a83d6ad570
https://git.kernel.org/stable/c/bf3709738d8a8cc6fa275773170c5c29511a0b24
https://git.kernel.org/stable/c/c53aa6a5086f03f19564096ee084a202a8c738c0
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