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High 7.5Published Mar 18, 2026

CVE-2026-27135nghttp2 Denial of service: Assertion failure due to the missing state validation

Updated under an hour ago ()

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It affects nghttp2 and 18 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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nghttp2 is an implementation of the Hypertext Transfer Protocol version 2 in C. Prior to version 1.68.1, the nghttp2 library stops reading the incoming data when user facing public API `nghttp2_session_terminate_session` or `nghttp2_session_terminate_session2` is called by the application. They might be called internally by the library when it detects the situation that is subject to connection error. Due to the missing internal state validation, the library keeps reading the rest of the data after one of those APIs is called. Then receiving a malformed frame that causes FRAME_SIZE_ERROR causes assertion failure. nghttp2 v1.68.1 adds missing state validation to avoid assertion failure. No known workarounds are available.

CVSS
7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-617
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Modified
Record last updated
Oct 15, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
nghttp2 nghttp2
nghttp2:nghttp2 (from the name)
before 1.68.1
CNA record
Red Hat JBoss Core Services for RHEL 8
redhat:jboss_core_services
from 0:1.64.0-3.el8jbcs not affected
CISA ADP
from 1:22.22.2-1.el10_1 not affected
CISA ADP
from 1:22.22.2-2.el10_0 not affected
CISA ADP
from 0:1.33.0-3.el8_2.4 not affected
CISA ADP
from 0:1.33.0-4.el8_4.3 not affected
CISA ADP
from 0:1.33.0-4.el8_6.3 not affected
CISA ADP
from 0:1.33.0-4.el8_6.3 not affected
CISA ADP
from 9040020260421133644.rhel9 not affected
CISA ADP
from 412.86.202605271418-0 not affected
CISA ADP
from 7.13.5-4.1777325677 not affected
CISA ADP
Red Hat Red Hat AI Inference Server 3.2
redhat:ai_inference_server
from 1779223654 not affected
CISA ADP
from 1778101579 not affected
CISA ADP
from 1.68.1-1.hum1 not affected
CISA ADP
from 1776868961 not affected
CISA ADP
from 1776868774 not affected
CISA ADP
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
nghttp2 nghttp2
nghttp2:nghttp2
before 1.68.1
NVD

References

  • x-refsource-confirm, patch, vendor-advisory
  • x-refsource-misc, patch
  • mailing-list, third-party-advisory

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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