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Fencer Intel
low 3.5

CVE-2025-8129 json

KoaJS Koa HTTP Header response.js back redirect

published last yr. modified 4mo ago also GHSA-jgmv-j7ww-jx2x , EUVD-2025-22567

cvss
3.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

A vulnerability, which was classified as problematic, was found in KoaJS Koa up to 3.0.0. Affected is the function back in the library lib/response.js of the component HTTP Header Handler. The manipulation of the argument Referrer leads to open redirect. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.

Patch / fix

  • npm koa 2.16.2, 3.0.1
  • koajs koa 2.16.2

Is CVE-2025-8129 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-8129 updated cvss 6.1

koa: KoaJS Koa HTTP Header response.js back redirect

  • Red Hat OpenShift Service Mesh 2 openshift-service-mesh/pilot-rhel8, openshift-service-mesh/grafana-rhel8, openshift-service-mesh/proxyv2-rhel9, openshift-service-mesh/istio-cni-rhel8, openshift-service-mesh/ratelimit-rhel8, openshift-service-mesh/istio-rhel8-operator, +2 more Red Hat OpenShift Service Mesh 3 openshift-service-mesh/istio-cni-rhel9, openshift-service-mesh/istio-pilot-rhel9, openshift-service-mesh/istio-proxyv2-rhel9, openshift-service-mesh/istio-rhel9-operator, openshift-service-mesh/istio-must-gather-rhel9, openshift-service-mesh/istio-sail-operator-bundle, +2 more Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/koajs/koa/issues/1892 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/koajs/koa/issues/1892#issue-3213028583 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
CNA 3.1 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA 3.0 3.5 CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
CNA 4.0 2.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N
GitHub 3.1 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm koa
>=2.0.0, <2.16.2
>=3.0.0-alpha.0, <3.0.1
2.16.2
3.0.1

Affected products

  • KoaJS Koa

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.