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Vulnerabilities

Vulnerability · CVE-2026-23011

In the Linux kernel, the following vulnerability has been resolved: ipv4: ip_gre: make ipgre_header() robust Analog to commit db5b4e39c4e6 ("ip6_gre: make ip6gre_heade…

Published Jan 25, 2026 · catalog updated Oct 15, 2026 · linux kernel

Check if you run it

No confirmed exploitation is on record for CVE-2026-23011. EPSS is 0.21%. Act only if a listed version of linux kernel is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.21%
Remediation
Advisory link
Affected products
cpe linux/linux kernel

In the Linux kernel, the following vulnerability has been resolved: ipv4: ip_gre: make ipgre_header() robust Analog to commit db5b4e39c4e6 ("ip6_gre: make ip6gre_header() robust") Over the years, syzbot found many ways to crash the kernel in ipgre_header() [1]. This involves team or bonding drivers ability to dynamically change their dev->needed_headroom and/or dev->hard_header_len In this particular crash mld_newpack() allocated an skb with a too small reserve/headroom, and by the time mld_sendpack() was called, syzbot managed to attach an ipgre device. [1] skbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000 data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0 kernel BUG at net/core/skbuff.c:213 ! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: mld mld_ifc_work RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213 Call Trace: skb_under_panic net/core/skbuff.c:223 [inline] skb_push+0xc3/0xe0 net/core/skbuff.c:2641 ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897 dev_hard_header include/linux/netdevice.h:3436 [inline] neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318 mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe linux/linux kernel3.10
  • cpe linux/linux kernel6.19

How to fix CVE-2026-23011

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-23011. EPSS is 0.21%. Act only if a listed version of linux kernel is installed.

Which versions are affected?

Compare what you have installed with linux/linux kernel 3.10; linux/linux kernel 6.19. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.21%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 25, 2026 · NIST NVD

    Detected

    In the Linux kernel, the following vulnerability has been resolved: ipv4: ip_gre: make ipgre_header() robust Analog to commit db5b4e39c4e6 ("ip6_gre: make ip6gre_header() robust") Over the years, syzbot found many ways to crash the kernel in ipgre_header() [1]. This involves team or bonding drivers ability to dynamically change their dev->needed_headroom and/or dev->hard_header_len In this particu

  2. Oct 15, 2026 · NIST NVD

    Updated

    In the Linux kernel, the following vulnerability has been resolved: ipv4: ip_gre: make ipgre_header() robust Analog to commit db5b4e39c4e6 ("ip6_gre: make ip6gre_header() robust") Over the years, syzbot found many ways to crash the kernel in ipgre_header() [1]. This involves team or bonding drivers ability to dynamically change their dev->needed_headroom and/or dev->hard_header_len In this particu

Sources

  • CVE.orgVulnerability recordCVE-2026-23011

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-23011

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-23011

    In the Linux kernel, the following vulnerability has been resolved: ipv4: ip_gre: make ipgre_header() robust Analog to commit db5b4e39c4e6 ("ip6_gre: make ip6gre_header() robust") Over the years, syzbot found many ways to crash the kernel in ipgre_header() [1]. This involves

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.