How severe is CVE-2026-5078?

CVE-2026-5078 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-5078 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-5078?

CVE-2026-5078 affects Morgan Project Morgan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-5078?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-5078 have an EU (EUVD) identifier?

Yes. CVE-2026-5078 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34067.

When was CVE-2026-5078 published?

CVE-2026-5078 was published on 2026-06-03 and last updated on 2026-06-17.

CVE-2026-5078

CVE-2026-5078 is a medium-severity vulnerability in Morgan Project Morgan with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-117.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-34067
Weakness: CWE-117
Affected product: Morgan Project Morgan
Published: 2026-06-03
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-5078?: 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.
How severe is CVE-2026-5078?: CVE-2026-5078 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-5078 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-5078?: CVE-2026-5078 affects Morgan Project Morgan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-5078?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-5078 have an EU (EUVD) identifier?: Yes. CVE-2026-5078 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34067.
When was CVE-2026-5078 published?: CVE-2026-5078 was published on 2026-06-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:morgan_project:morgan:*:*:*:*:*:node.js:*:*

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