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CVE Record

CVE-2024-26995: usb: typec: tcpm: Correct the PDO counting in pd_set

In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: Correct the PDO counting in pd_set Off-by-one errors happen because nr_snk_pdo and nr_src_pdo are incorrectly added one. The index of the loop is equal to the number of PDOs to be updated when leaving the loop and it doesn't need to be added one. When doing the power negotiation, TCPM relies on the "nr_snk_pdo" as the size of the local sink PDO array to match the Source capabilities of the partner port. If the off-by-one overflow occurs, a wrong RDO might be sent and unexpected power transfer might happen such as over voltage or over current (than expected). "nr_src_pdo" is used to set the Rp level when the port is in Source role. It is also the array size of the local Source capabilities when filling up the buffer which will be sent as the Source PDOs (such as in Power Negotiation). If the off-by-one overflow occurs, a wrong Rp level might be set and wrong Source PDOs will be sent to the partner port. This could potentially cause over current or port resets.

UnknownCVSS not scoredNot KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw affects USB Type-C Power Delivery negotiation. A counting mistake can make the kernel describe or choose the wrong power data, potentially causing unexpected power transfer such as higher voltage/current than intended or port resets. The sources do not report active exploitation or a CVSS score.

Executive priority

Treat this as a targeted kernel maintenance issue, not an internet-scale emergency. Prioritize laptops, embedded systems, docks, and devices relying on USB-C Power Delivery. Move through normal kernel patch cycles unless vendor guidance or fleet exposure indicates higher urgency.

Technical view

In the TCPM USB Type-C code, pd_set incorrectly increments nr_snk_pdo and nr_src_pdo after loops. Those values size local sink/source PDO arrays and influence RDO selection, Rp level, and advertised source PDOs. The resolved issue is an off-by-one overflow in PDO counting during power negotiation.

Likely exposure

Exposure is most relevant to Linux systems using affected kernel builds with USB Type-C Power Delivery/TCPM support. The bundle lists Linux kernel 6.8-related versions and references stable kernel fixes and Fedora advisories. Systems without affected USB-C PD paths are less likely to be exposed.

Exploitation context

No active exploitation is cited, and the CVE is not listed as CISA KEV in the provided bundle. The described impact is tied to USB Type-C power negotiation behavior, suggesting exploitation would depend on hardware, kernel version, driver path, and partner port interaction.

Researcher notes

The key evidence is the kernel description: off-by-one PDO counts can corrupt power negotiation decisions, including RDO, Rp level, and advertised PDOs. Sources do not provide exploit details, CVSS, CWE mapping, or confirmed affected hardware models, so validation should remain evidence-based and distribution-specific.

Mitigation direction

  • Check vendor kernel advisories for CVE-2024-26995 applicability.
  • Update to a kernel build containing the referenced stable fixes.
  • Apply Fedora kernel updates where Fedora advisories match deployed systems.
  • Prioritize devices using USB-C Power Delivery or TCPM paths.
  • Avoid inventing local workarounds; follow Linux distribution guidance.

Validation and detection

  • Inventory Linux kernel versions on USB-C capable systems.
  • Confirm whether TCPM or USB Type-C Power Delivery is enabled.
  • Map installed kernels against vendor advisories for CVE-2024-26995.
  • Verify patched kernels include the referenced stable commits.
  • Review change records for kernel updates after May 2024.
Prepared
Confidence
medium
Sources
7

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
3Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxcd099cde4ed264403b434d8344994f97ac2a4349, cd099cde4ed264403b434d8344994f97ac2a4349unaffected
LinuxLinux6.8, 0, 6.8.8, 6.9affected
Weakness

CWE details

No CWE listed

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