9.8

CVE-2026-53221: linux Improper Input Validation

CVSS: 9.8v3.1CriticalModified
AliasesUBUNTU-CVE-2026-53221DEBIAN-CVE-2026-53221CGA-2336-x984-hv8c
Published 25-06-2026Last modified 19-10-2026
Open JSON

Vulnerability summary

CVE-2026-53221 is a critical (CVSS 9.8) Improper Input Validation vulnerability in linux. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 46.4% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.58%
0%100%
Low · +0.06 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 51 · Related 51
MGASA-2026-0312OPENSUSE-SU-2026:21555-1SUSE-SU-2026:23066-1SUSE-SU-2026:23068-1SUSE-SU-2026:23193-1SUSE-SU-2026:23194-1

Timeline

  1. 25-06-2026
    PublishedVulnerability first disclosed.
  2. 19-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() In vti6_tnl_lookup(), when an exact match for a tunnel fails, the code falls back to searching for wildcard tunnels: - Tunnels matching the packet's local address, with any remote address wildcard remote). - Tunnels matching the packet's remote address, with any local address (wildcard local). However, vti6 stores all these different types of tunnels in the same hash table (ip6n->tnls_r_l) prone to hash collisions. The bug is that the fallback search loops in vti6_tnl_lookup() were missing checks to ensure that the candidate tunnel actually has a wildcard address.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

0.58%

Chance of exploitation in the next 30 days

Percentile

46%

Versus all other CVEs

30-day change

+0.06 pp

From 0.51% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.58%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu168 products
  • linux< 4.4.0-288.322 | < 4.15.0-260.272 | < 5.4.0-241.261 | < 5.15.0-194.204 | < 6.8.0-142.142 | All versions (No fix recorded) | < 7.0.0-29.29
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 4.4.0-1159.165 | < 4.4.0-1197.212 | < 4.15.0-1197.210 | < 5.4.0-1164.175 | < 5.15.0-1116.123 | < 6.8.0-1065.68 | All versions (No fix recorded) | < 7.0.0-1010.10
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Chainguard13 products
  • linux-aws-6.12< 6.12.95-r0
  • linux-aws-6.18< 6.18.38-r0
  • linux-azure-6.12< 6.12.95-r0
  • linux-azure-6.18< 6.18.38-r0
  • linux-gcp-6.12< 6.12.95-r0
Linux2 products
  • linux≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < c327fa4fca31415431202e063767a7ae342e19c6 | ≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < fc657ac0767c49839b3ef0b08dc0953ca30883f8 | ≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < 47fb3c2b4203556308e64354b3e78f2ce221d646 | ≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < f513f308cc4bdb4530d033431592ffbc29b7fca1 | ≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < 90fd4513315ca07da99cfd8549d3e553a7160f0d | ≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < 2abfb19bbb81958714ad1d43ebeb65b30394184b | ≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < 2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d | ≥ fbe68ee87522f6eaa10f9076c0a7117e1613f2f7, < a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9 | 3.19
  • linux_kernel≥ 3.19, < 5.10.259 | ≥ 5.11, < 5.15.210 | ≥ 5.16, < 6.1.176 | ≥ 6.2, < 6.6.143 | ≥ 6.7, < 6.12.94 | ≥ 6.13, < 6.18.36 | ≥ 6.19, < 7.0.13 | 7.1:rc1 | 7.1:rc2 | 7.1:rc3 | 7.1:rc4 | 7.1:rc5 | 7.1:rc6 | 7.1:rc7
Debian1 product
  • linux< 6.1.176-1 | < 6.12.94-1 | < 7.0.13-1

4 vendors · 184 products

References

54 links
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