CVE-2026-31668
seg6: separate dst_cache for input and output paths in seg6 lwtunnel
Description
In the Linux kernel, the following vulnerability has been resolved: seg6: separate dst_cache for input and output paths in seg6 lwtunnel The seg6 lwtunnel uses a single dst_cache per encap route, shared between seg6_input_core() and seg6_output_core(). These two paths can perform the post-encap SID lookup in different routing contexts (e.g., ip rules matching on the ingress interface, or VRF table separation). Whichever path runs first populates the cache, and the other reuses it blindly, bypassing its own lookup. Fix this by splitting the cache into cache_input and cache_output, so each path maintains its own cached dst independently.
INFO
Published Date :
April 24, 2026, 3:16 p.m.
Last Modified :
April 27, 2026, 8:08 p.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Split the dst_cache into cache_input and cache_output.
- Ensure each path maintains its own cached dst independently.
- Apply kernel updates or patches for seg6 lwtunnel.
Public PoC/Exploit Available at Github
CVE-2026-31668 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
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information, practical solutions, and valuable tools related to
CVE-2026-31668.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-31668 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-31668
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
DSA and DLA for Debian last 14 days
Python
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The following list is the news that have been mention
CVE-2026-31668 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-31668 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Apr. 27, 2026
Action Type Old Value New Value Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:4.10:-:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.203 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.169 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.10.1 up to (excluding) 5.10.253 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.23 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 6.19.13 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.135 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.82 Added Reference Type kernel.org: https://git.kernel.org/stable/c/17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6a Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/1dec91d3b1cefb82635761b7812154af3ef46449 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/57d0374d14fa667dec6952173b93e7e84486d5c9 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/6305ad032b03d2ea4181b953a66e19a9a6ed053c Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/750569d6987a0ff46317a4b86eb3907e296287bf Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/84d458018b147176b259347103fccb7e93abd2b1 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/c3812651b522fe8437ebb7063b75ddb95b571643 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/fb56de5d99218de49d5d43ef3a99e062ecd0f9a1 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 24, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: seg6: separate dst_cache for input and output paths in seg6 lwtunnel The seg6 lwtunnel uses a single dst_cache per encap route, shared between seg6_input_core() and seg6_output_core(). These two paths can perform the post-encap SID lookup in different routing contexts (e.g., ip rules matching on the ingress interface, or VRF table separation). Whichever path runs first populates the cache, and the other reuses it blindly, bypassing its own lookup. Fix this by splitting the cache into cache_input and cache_output, so each path maintains its own cached dst independently. Added Reference https://git.kernel.org/stable/c/17d87d42874f5d6c1a0ccc6d9190dfe82a9a7a6a Added Reference https://git.kernel.org/stable/c/1dec91d3b1cefb82635761b7812154af3ef46449 Added Reference https://git.kernel.org/stable/c/57d0374d14fa667dec6952173b93e7e84486d5c9 Added Reference https://git.kernel.org/stable/c/6305ad032b03d2ea4181b953a66e19a9a6ed053c Added Reference https://git.kernel.org/stable/c/750569d6987a0ff46317a4b86eb3907e296287bf Added Reference https://git.kernel.org/stable/c/84d458018b147176b259347103fccb7e93abd2b1 Added Reference https://git.kernel.org/stable/c/c3812651b522fe8437ebb7063b75ddb95b571643 Added Reference https://git.kernel.org/stable/c/fb56de5d99218de49d5d43ef3a99e062ecd0f9a1