CVE-2026-98764usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC
- —Not scoredno CVSS score yet
- 0.18%Exploitation in 30 daysEPSS · top 93% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC When user space sets up FunctionFS with only full-speed descriptors (e.g., flags = FUNCTIONFS_HAS_FS_DESC) and the gadget operates at a higher speed (such as USB_SPEED_HIGH or USB_SPEED_SUPER), config_ep_by_speed() detects that the function lacks descriptors for the current speed, logs a warning, and falls back to full-speed descriptors. The endpoint is then successfully enabled via usb_ep_enable(), and epfile->ep becomes valid. However, when user space subsequently issues the FUNCTIONFS_ENDPOINT_DESC ioctl to query the endpoint descriptor, ffs_epfile_ioctl() selects the descriptor index solely based on gadget->speed: switch (epfile->ffs->gadget->speed) { case USB_SPEED_SUPER: case USB_SPEED_SUPER_PLUS: desc_idx = 2; break; case USB_SPEED_HIGH: desc_idx = 1; break; default: desc_idx = 0; } desc = epfile->ep->descs[desc_idx]; memcpy(&desc1, desc, desc->bLength); Because user space only supplied full-speed descriptors, epfile->ep->descs[1] is NULL. Dereferencing desc->bLength triggers an immediate kernel NULL pointer dereference panic. Fix this by falling back through lower speed descriptors if the current speed descriptor was not supplied, matching the fallback logic in config_ep_by_speed() and historical f_fs behavior. If still missing, fall back to epfile->ep->ep->desc (the active descriptor), and return -EINVAL safely if no valid descriptor is found. In addition, mark desc as const to match struct usb_ep::desc and avoid discarding qualifiers.
Timeline
ID reserved
By Linux
- 23 days later
· 23 days later
Published
- 12 days later
· 12 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.18% · top 93% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < c5f452e057df6ef89300523d13ad6833bfd199cd
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < 7ef0ad5f462fa95bc4c6647d097d7c0384245b9c
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < 06ac8609d6d185ac18c1d6a6a8a9b99e398bd124
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < 9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < 7811d8e26c77f8eea79e22d0d14c67ec0658b348
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < 35ab269602e1f7c4c0fe6ea3477264bea77eced3
- affected c559a353410939c0884e83bdb0e2420a986ac53b – < 9cd072788c76595529eb38f42bf94d23852f8534
- affected 3.18
- unaffected < 3.18
- unaffected 5.10.273 – ≤ 5.10.*
- unaffected 5.15.224 – ≤ 5.15.*
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.113 – ≤ 6.12.*
- unaffected 6.18.56 – ≤ 6.18.*
- unaffected 7.2.10 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/c5f452e057df6ef89300523d13ad6833bfd199cd (opens in a new tab)
- https://git.kernel.org/stable/c/e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad (opens in a new tab)
- https://git.kernel.org/stable/c/7ef0ad5f462fa95bc4c6647d097d7c0384245b9c (opens in a new tab)
- https://git.kernel.org/stable/c/06ac8609d6d185ac18c1d6a6a8a9b99e398bd124 (opens in a new tab)
- https://git.kernel.org/stable/c/9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3 (opens in a new tab)
- https://git.kernel.org/stable/c/7811d8e26c77f8eea79e22d0d14c67ec0658b348 (opens in a new tab)
- https://git.kernel.org/stable/c/35ab269602e1f7c4c0fe6ea3477264bea77eced3 (opens in a new tab)
- https://git.kernel.org/stable/c/9cd072788c76595529eb38f42bf94d23852f8534 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-103849 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-98764)Record last updated .