CVE-2026-78689Network attack vectorHinoki check available

Worker denial of service via prefix-list heap overwrite

Published Sep 2, 2026 · Updated Sep 3, 2026

Heap buffer overflow in F5 NGINX JavaScript 0.7.10 through 1.0.0 allows remote attackers to crash workers via crafted XML prefix lists. The xml.exclusiveC14n() namespace parser writes past a heap allocation when processing an externally controlled InclusiveNamespaces PrefixList. Exposure requires a configuration that passes the list to the method; the official nginx-saml flow does so before signature verification, causing worker crashes with njs or memory growth with QuickJS.

CVSS severity8.1
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Heap buffer overflow in F5 NGINX JavaScript 0.7.10 through 1.0.0 allows remote attackers to crash workers via crafted XML prefix lists. The xml.exclusiveC14n() namespace parser writes past a heap allocation when processing an externally controlled InclusiveNamespaces PrefixList. Exposure requires a configuration that passes the list to the method; the official nginx-saml flow does so before signature verification, causing worker crashes with njs or memory growth with QuickJS.

The record

CVE
CVE-2026-78689
Published
Sep 2, 2026
Updated
Sep 3, 2026
Vendor
F5 Networks
Product
NGINX JavaScript
Classifications
CWE-122, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.7.10 <1.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

F5 Networks · NGINX JavaScriptversion=0.7.10 <1.0.1

Published CVSS scores

9.2F5CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.1F5CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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