CVE-2026-98122: Linux kernel · vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in e12c903fd13c6261b98ca18d8f70ac26e739e2f8 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in e12c903fd13c6261b98ca18d8f70ac26e739e2f8, 71203a41d6fa2fa0ea2f3a7541987958bd3694fd, 74e2a56c82209b0335b53e25f19f9b0590e2483d +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available and has been applied in the Linux kernel source code by rejecting the all-zeros address in vxlan_mdb_is_valid_source(). Users and administrators should update to the fixed Linux kernel versions identified by the commits e12c903fd13c6261b98ca18d8f70ac26e739e2f8, 71203a41d6fa2fa0ea2f3a7541987958bd3694fd, 74e2a56c82209b0335b53e25f19f9b0590e2483d, 069d5527bb0f229e528fa88c6b72f15060c373f2, or 4aa61c88b4e292e10abdfd791334b8272108d68a. No additional mitigations are indicated by the vendor advisory.
Description
CVE-2026-98122 is a use-after-free vulnerability in the Linux kernel's VXLAN multicast database (mdb) handling, specifically in the function vxlan_mdb_remote_src_del(). The flaw arises when the all-zeros address is accepted as a valid source, causing key aliasing that leads to freeing an entry twice. This can result in a kernel crash or potential escalation of privileges. The vulnerability affects Linux kernel version 6.4 and was fixed by rejecting the all-zeros address in the validation function. The issue can be triggered by unprivileged users in a new user and network namespace due to netns-scoped MDB operations.
References
- git.kernel.org/stable/c/069d5527bb0f229e528fa88c6b72f15060c373f2 (opens in a new tab)
- git.kernel.org/stable/c/e12c903fd13c6261b98ca18d8f70ac26e739e2f8 (opens in a new tab)
- git.kernel.org/stable/c/74e2a56c82209b0335b53e25f19f9b0590e2483d (opens in a new tab)
- git.kernel.org/stable/c/71203a41d6fa2fa0ea2f3a7541987958bd3694fd (opens in a new tab)
- git.kernel.org/stable/c/4aa61c88b4e292e10abdfd791334b8272108d68a (opens in a new tab)