CVE-2026-5078: morgan vulnerable to Log Forging via unneutralized control characters in :remote-user
Affects morganSource GCVE Database
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
- 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:NExploitation evidence
Disclosed: evidence found.
CVE published 10 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| npmmorgan | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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`.