CVE-2026-48981 json
pam_usb: xmlReadFile flags=0 permits XXE network entity fetching in conf.c
published 2026-06-18 4 mo ago modified 2026-10-26 14 d ago also EUVD-2026-37934
- cvss
- 6.7
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 4%
- public exploits
- 0
- none known
Summary
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions prior to 0.9.2, pam_usb calls xmlReadFile() with flags=0 when loading the configuration file, allowing libxml2 to process external entity references (XXE), potentially making outbound network connections or local file reads at XML parse time from the context of the authenticating process. The vulnerability requires the configuration file to contain crafted XML entity references. Since pam_usb.conf is root-owned, direct exploitation requires prior write access to the config, but the defence-in-depth impact is significant given that pam_usb.so runs in setuid contexts (sudo, su). This issue has been fixed in version 0.9.2.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.7 | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:L |
Affected products
- mcdope pam_usb
Classification
- Weakness
-
- CWE-611 Improper Restriction of XML External Entity Reference
References
Sources
- CVE List CVE-2026-48981
- NVD CVE-2026-48981
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