CVE-2026-48984
CVE-2026-48984 — pam_usb: xfree() does not call explicit_bzero — sensitive cryptographic material may linger in freed heap
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions 0.9.1 and below, the xfree() memory release helper in calls free() without first zeroing the buffer contents, releasing heap-allocated buffers containing sensitive data — including one-time pad bytes read from disk — without clearing, leaving the sensitive content in freed heap memory until it happens to be overwritten by a subsequent allocation. On a system where a use-after-free condition exists, or where a heap inspection primitive becomes available, this could allow recovery of pad values or other authentication material from freed memory regions. This is a defence-in-depth requirement consistent with prior hardening work in this codebase (GHSA-vx6f-rrqr-j87c applied explicit_bzero to some pad paths; this issue generalises the pattern to the central deallocation helper).
Published Updated Sources: cvelistV5, GitHub_M
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
0%
chance of exploitation in 30 days
CVSS base
4.7
MEDIUM
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script all four kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (1)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 4.7 | CVSS 3.1 | MEDIUM | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-14
- CWE-226
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
- T1005Data from Local System
- T1552.004Unsecured Credentials: Private Keys
References
2 on the record
- github.com/mcdope/pam_usb/security/advisories/GHSA-rmp6-wfrq-wrrc
x_refsource_CONFIRM
- github.com/mcdope/pam_usb/releases/tag/0.9.2
x_refsource_MISC
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.