CVE-2026-63964

UnknownEPSS 0.21%

Last modified

CVE-2026-63964 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: ccg: reject firmware images without a ':' record header do_flash() locates the first .cyacd record with p = strnchr(fw->data, fw->size, ':'); while (p < eof) { s = strnchr(p + 1, eof - p - 1, ':'); ... } If the firmware image contains no ':' byte, strnchr() returns NULL. NULL compares less than the valid kernel pointer eof, so the loop body runs and strnchr() is called with p + 1 == (void *)1 and a length of roughly (unsigned long)eof, causing a wonderful crash. The not_signed_fw fallthrough earlier in do_flash() and the chip-state branches in ccg_fw_update_needed() allow an unsigned blob to reach this loop, so a root user who can place a crafted file under /lib/firmware and write the do_flash sysfs attribute can trigger the oops. Bail out with -EINVAL when the initial strnchr() returns NULL.. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: ccg: reject firmware images without a ':' record header do_flash() locates the first .cyacd record with p = strnchr(fw->data, fw->size, ':'); while (p < eof) { s = strnchr(p + 1, eof - p - 1, ':'); ... } If the firmware image contains no ':' byte, strnchr() returns NULL. NULL compares less than the valid kernel pointer eof, so the loop body runs and strnchr() is called with p + 1 == (void *)1 and a length of roughly (unsigned long)eof, causing a wonderful crash. The not_signed_fw fallthrough earlier in do_flash() and the chip-state branches in ccg_fw_update_needed() allow an unsigned blob to reach this loop, so a root user who can place a crafted file under /lib/firmware and write the do_flash sysfs attribute can trigger the oops. Bail out with -EINVAL when the initial strnchr() returns NULL.

Metrics

EPSS Probability
0.21%

11.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < b41dfc033fe594e152648050e95b9489cd53e9e3; >= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < 2f395ca1263bd181995eb829f5943a83a20db213; >= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < 6526f8684f72391138353642af908803ba70795e; >= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < 3f432b8203066c26770fe6ea591361f10021dd6b; >= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < c4ee519b06389e59ba2d6aa722fcc4a02a8bbcbb; >= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < a38ed87818b2419090fb1a6338ddce6842b65dfa; >= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < c8460de584fe5415d212cfdd127d4db90835a450; >= 5c9ae5a87573d38cfc4c740aafda2fa6ce06e401, < d7486952bf74e546ee3748fb14b2d07881fa6273
LinuxLinux5.2

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-63964?
In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: ccg: reject firmware images without a ':' record header do_flash() locates the first .cyacd record with p = strnchr(fw->data, fw->size, ':'); while (p < eof) { s = strnchr(p + 1, eof - p - 1, ':'); ... } If the firmware image contains no ':' byte, strnchr() returns NULL. NULL compares less than the valid kernel pointer eof, so the loop body runs and strnchr() is called with p + 1 == (void *)1 and a length of roughly (unsigned long)eof, causing a wonderful crash. The not_signed_fw fallthrough earlier in do_flash() and the chip-state branches in ccg_fw_update_needed() allow an unsigned blob to reach this loop, so a root user who can place a crafted file under /lib/firmware and write the do_flash sysfs attribute can trigger the oops. Bail out with -EINVAL when the initial strnchr() returns NULL.
How severe is CVE-2026-63964?
Severity scoring for CVE-2026-63964 is pending analysis. The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-63964?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST