Skip to content
Fencer Intel
medium 5.3

CVE-2026-5078 json

morgan vulnerable to Log Forging via unneutralized control characters in :remote-user

published 5mo ago modified 2mo ago also EUVD-2026-34067 , GHSA-4vj7-5mj6-jm8m

cvss
5.3
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 26%
public exploits
0
none known

Summary

Impact: The morgan logging middleware's :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user.

Patch / fix

  • npm morgan 1.11.0
  • morgan morgan 1.11.0
  • node-morgan Debian 14 1.12.0+~1.9.10-1

debian advisories DEBIAN-CVE-2026-5078

  • nodejs24 hummingbird 1 24.18.0-0.3.hum1
  • nodejs24-bin hummingbird 1 24.18.0-0.3.hum1
  • nodejs24-npm hummingbird 1 11.16.0-1.24.18.0.0.3.hum1
  • nodejs24-libs hummingbird 1 24.18.0-0.3.hum1
  • nodejs24-npm-bin hummingbird 1 24.18.0-0.3.hum1
  • nodejs24-full-i18n hummingbird 1 24.18.0-0.3.hum1

red hat advisories RHSA-2026:38236

Is CVE-2026-5078 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.

Check with Fencer

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-2026-5078 updated cvss 5.3

morgan: morgan: Log forgery due to unneutralized control characters

  • Red Hat Confidential Compute Attestation openshift-sandboxed-containers/osc-pccs Red Hat Cryostat 4 cryostat/cryostat-openshift-console-plugin-rhel9 Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Enterprise Linux 9 sgx-mpa, tdx-qgs, sgx-libs, sgx-pccs, linux-sgx, sgx-common, +2 more Red Hat Enterprise Linux 10 linux-sgx Red Hat Fuse 7 morgan
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images nodejs20, nodejs25
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Openshift Data Foundation 4 odf4/mcg-core-rhel9, rhceph-dev/odf4-mcg-core-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images nodejs24 24.18.0-0.3.hum1, nodejs24-bin 24.18.0-0.3.hum1, nodejs24-libs 24.18.0-0.3.hum1, nodejs24-npm-bin 24.18.0-0.3.hum1, nodejs24-full-i18n 24.18.0-0.3.hum1, nodejs24-npm 11.16.0-1.24.18.0.0.3.hum1
    fixed: vendor fix RHSA-2026:38236
  • Red Hat Hardened Images nodejs22, nodejs26
    not affected: vulnerable code not present

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
none
Automatable
yes
Technical impact
partial
Assessed
5mo ago

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm morgan
>=1.2.0, <1.11.0
1.11.0

Affected products

  • morgan morgan

Classification

Weakness
  • CWE-117 Improper Output Neutralization for Logs

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.

The maintainers of expressjs/morgan published their own advisory on GitHub. Reviewed sources take precedence over it.