Security readout for executives and security teams
Plain-English summary
pam_usb before 0.9.1 can mishandle remote login checks when configured with deny_remote=false. That setting is commonly used for display managers, but it also skips the PAM_RHOST remote-client check, allowing a remote XDMCP authentication path to reach USB authentication instead of being rejected.
Executive priority
Prioritize remediation where pam_usb protects interactive Linux logins and remote display access is enabled. This is high severity but currently lacks cited evidence of active exploitation.
Technical view
In pusb_do_auth(), the PAM_RHOST check is gated behind opts.deny_remote. When deny_remote=false, remote-client detection is skipped. Sources describe this as an authentication bypass affecting mcdope pam_usb versions before 0.9.1, with CVSS 8.1 and CWE-863 improper authorization.
Likely exposure
Exposure is most likely on Linux systems using pam_usb before 0.9.1 with PAM services configured deny_remote=false, especially display-manager services such as gdm-password or lightdm where XDMCP remote authentication is enabled or reachable.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. The described attack surface is network-reachable but high complexity, and the named remote path is XDMCP authentication.
Researcher notes
Focus on PAM service configuration and remote-session behavior. The core issue is authorization logic: disabling deny_remote also bypasses PAM_RHOST evaluation. Evidence is limited to the CVE record, GitHub advisory, and related issue.
Mitigation direction
- Upgrade pam_usb to version 0.9.1 or later.
- Review PAM services using pam_usb with deny_remote=false.
- Disable or restrict XDMCP where it is not required.
- Check vendor or distribution guidance for package availability.
- Treat display-manager PAM changes as operationally sensitive.
Validation and detection
- Inventory installed pam_usb versions across Linux endpoints and servers.
- Inspect PAM configuration for pam_usb deny_remote=false entries.
- Confirm whether XDMCP is enabled or externally reachable.
- Verify upgraded systems report pam_usb 0.9.1 or later.
- Review authentication logs for unusual remote display-manager attempts.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-863: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-48064 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9GitHub_MVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/mcdope/pam_usb/security/advisories/GHSA-w38v-cw9r-x9p6CVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/mcdope/pam_usb/issues/348CVE reference, GitHub_M · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Incorrect Authorization
Incorrect Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.