CVE-2026-98255: linux

CVSS: UnknownReceived
AliasesUBUNTU-CVE-2026-98255DEBIAN-CVE-2026-98255
Published 06-10-2026Last modified 19-10-2026
Open JSON

Vulnerability summary

CVE-2026-98255 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.6% of scored vulnerabilities.

Overall risk
0/100
0100
Minimal · default modelHow is this calculated?
CVSS score
Not scored
010
No CVSS score recorded
EPSS score
0.18%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:12131-1

Timeline

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

Description

In the Linux kernel, the following vulnerability has been resolved: tcp: exclude old ACKs from tcp fast path Exclude old ACKs before SND.UNA from the tcp fast path as well as ACKs after SND.NXT. Such ACKs will fall through to the slow path, where tcp_ack() performs the appropriate validation and challenge ACK handling according to RFC5961 and Commit 3d501dd326fb1c7 ("tcp: do not accept ACK of bytes we never sent"). This prevents old ACKs from being accepted or modifying connection state as part of the fast path before appropriate ACK validation is applied. In particular, this prevents payload carried by a segment with an excessively old ACK from advancing RCV.NXT before the ACK is rejected.

CVSS metrics

Risk metrics not yet published.

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

8%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

06-10-202621-10-2026
EPSS score
0.18%

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

No weakness data has been published for this record.

Affected systems

Ubuntu168 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian1 product
  • linuxAll versions (No fix recorded) | < 6.1.190-1 | < 6.12.113-1 | < 7.2.8-1
Linux1 product
  • linux≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < 07cacab90290f795bad2e566790f4ba8e84cdf5f | ≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < 6eb9b697f50b73b9684e466c1e97f4ca8e947a59 | ≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < b86e1e5a4bbcbbccde8b7a3d3486604b581f6628 | ≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < 1c8448db5cf35a13d82b0c9004ffdb49358883e7 | ≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < 8309dc2cc360056aa9cd2acfbfc25930798c3b66 | ≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < ff037920c688ae6ca1153fec01e90e6782712455 | ≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < 8205ac5ddb42a1843fa8d6a8c295b5c7f4f8c6ed | ≥ 31770e34e43d6c8dee129bfee77e56c34e61f0e5, < f81e6c3fb06327bc49cdd6e559845293ba06a704 | 4.14

3 vendors · 170 products

References

12 links
Show all 12 references