CVE-2026-98621
Published: October 21, 2026Last modified: October 21, 2026
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.
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Fixed (6.1.189-r0) |
| 25 LTS | linux-lts | Fixed (6.12.112-r0) | |
| Stream | linux-lts | Fixed (6.18.55-r0) |
References
- https://git.kernel.org/stable/c/1d664be4ca49d1696e85239236f4988dfc4653c3
- https://git.kernel.org/stable/c/1eeec0c51fd5598da44080ed96bbd9880021c28b
- https://git.kernel.org/stable/c/2566866fc30965d915d0b52b5c3323b362619f0e
- https://git.kernel.org/stable/c/40aeafbcbc7bc4018e8f74bbbb4d29ed8846f57f
- https://git.kernel.org/stable/c/43efb1f997e976f386aa89716f55870cd2cff9ad
- https://git.kernel.org/stable/c/4b9bc21b2396c396d88dd909caaf73d5be6ff593
- https://git.kernel.org/stable/c/97f907203321eee2cc9132d5c9eb47698fb41d35
- https://git.kernel.org/stable/c/c20f755338ca234e523dfc943719f194dfc1f903