9.1

CVE-2026-101356: Apache Tomcat: HTTP/2 request/response mix-up after error during async processing

Awaiting analysis
AliasesDEBIAN-CVE-2026-101356UBUNTU-CVE-2026-101356
Published 20-10-2026Last modified 20-10-2026

Vulnerability summary

CVE-2026-101356 is a critical (CVSS 9.1) vulnerability in apache software foundation apache tomcat. EPSS estimates a 0.50% chance of exploitation in the next 30 days, higher than 42.8% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.1 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.50%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 5 · Related 4
MGASA-2026-0568OPENSUSE-SU-2026:12254-1OPENSUSE-SU-2026:12255-1OPENSUSE-SU-2026:12256-1SUSE-SU-2026:4927-1

Timeline

  1. 20-10-2026
    PublishedVulnerability first disclosed.
  2. 20-10-2026
    Last modifiedVulnerability information updated.

Description

Incorrect object recycling and re-use vulnerability in Apache Tomcat affecting HTTP/2 processing of asynchronous servlets can trigger request and/or response mix-up between users. This issue affects Apache Tomcat: from 11.0.22 through 11.0.26, from 10.1.55 through 10.1.60, from 9.0.118 through 9.0.122. Users are recommended to upgrade to version 11.0.27, 10.1.61 or 9.0.123, which fixes the issue.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.50%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

21-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu6 products
  • tomcat10All versions (No fix recorded)
  • tomcat11All versions (No fix recorded)
  • tomcat6All versions (No fix recorded)
  • tomcat7All versions (No fix recorded)
  • tomcat8All versions (No fix recorded)
Debian3 products
  • tomcat10All versions (No fix recorded)
  • tomcat11All versions (No fix recorded)
  • tomcat9< 9.0.70-2
Apache software foundation1 product
  • apache tomcat≥ 11.0.22, ≤ 11.0.26 | ≥ 10.1.55, ≤ 10.1.60 | ≥ 9.0.118, ≤ 9.0.122

3 vendors · 10 products

References

8 links