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CVE-2026-98621

Unknown

Last modified

CVE-2026-98621 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: net: gue: reject invalid REMCSUM offsets The REMCSUM option carries an absolute checksum start and checksum field offset. gue_remcsum() passes them to skb_remcsum_process(), whose partial path stores offset - start in the u16 skb->csum_offset variable. If offset is less than start, this underflows. A forwarded packet can retain CHECKSUM_PARTIAL and reach a NETIF_F_HW_CSUM driver which trusts the metadata, leading skb_copy_and_csum_dev() to write two bytes about 64 KiB beyond the destination buffer. Reject reversed tuples in validate_gue_flags(), after the existing length validation, so all GUE parsers enforce the ordering in one place..

Description

In the Linux kernel, the following vulnerability has been resolved: net: gue: reject invalid REMCSUM offsets The REMCSUM option carries an absolute checksum start and checksum field offset. gue_remcsum() passes them to skb_remcsum_process(), whose partial path stores offset - start in the u16 skb->csum_offset variable. If offset is less than start, this underflows. A forwarded packet can retain CHECKSUM_PARTIAL and reach a NETIF_F_HW_CSUM driver which trusts the metadata, leading skb_copy_and_csum_dev() to write two bytes about 64 KiB beyond the destination buffer. Reject reversed tuples in validate_gue_flags(), after the existing length validation, so all GUE parsers enforce the ordering in one place.

Affected Software

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

VendorProductVersions
LinuxLinux>= fe881ef11cf0220f118816181930494d484c4883, < 4b9bc21b2396c396d88dd909caaf73d5be6ff593; >= fe881ef11cf0220f118816181930494d484c4883, < 43efb1f997e976f386aa89716f55870cd2cff9ad; >= fe881ef11cf0220f118816181930494d484c4883, < 1eeec0c51fd5598da44080ed96bbd9880021c28b; >= fe881ef11cf0220f118816181930494d484c4883, < 1d664be4ca49d1696e85239236f4988dfc4653c3; >= fe881ef11cf0220f118816181930494d484c4883, < 97f907203321eee2cc9132d5c9eb47698fb41d35; >= fe881ef11cf0220f118816181930494d484c4883, < 40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f; >= fe881ef11cf0220f118816181930494d484c4883, < c20f755338ca234e523dfc943719f194dfc1f903; >= fe881ef11cf0220f118816181930494d484c4883, < 2566866fc30965d915d0b52b5c3323b362619f0e
LinuxLinux4.0

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-98621?
In the Linux kernel, the following vulnerability has been resolved: net: gue: reject invalid REMCSUM offsets The REMCSUM option carries an absolute checksum start and checksum field offset. gue_remcsum() passes them to skb_remcsum_process(), whose partial path stores offset - start in the u16 skb->csum_offset variable. If offset is less than start, this underflows. A forwarded packet can retain CHECKSUM_PARTIAL and reach a NETIF_F_HW_CSUM driver which trusts the metadata, leading skb_copy_and_csum_dev() to write two bytes about 64 KiB beyond the destination buffer. Reject reversed tuples in validate_gue_flags(), after the existing length validation, so all GUE parsers enforce the ordering in one place.
How severe is CVE-2026-98621?
Severity scoring for CVE-2026-98621 is pending analysis.
How do I fix CVE-2026-98621?
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