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VulnerabilityPublished

CVE-2026-5078: morgan vulnerable to Log Forging via unneutralized control characters in :remote-user

Affects morganSource GCVE Database

0

Mentioned vulnerabilities

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.11.0 when convenient.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.11.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade morgan to 1.11.0.

Affected software

ProductAffectedFixed in
npmmorganAffected
  • >=1.2.0 <1.11.0
Fixed in
  • 1.11.0

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Description

### Impact Morgan's `:remote-user` token extracts the Basic auth username from the `Authorization` header and writes it to the log stream without neutralizing control characters. An attacker can send a crafted `Authorization: Basic` header containing CR/LF characters to inject forged log lines, corrupting the one-request-per-line structure of access logs. The built-in `combined`, `common`, `default`, and `short` formats are affected, as well as any custom format that includes `:remote-user`. ### Patches Users should upgrade to version 1.11.0. ### Workarounds Use a custom format string that does not include `:remote-user`.

References

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