CVE-2017-1000112

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 20.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2017-10-05 · updated 2026-06-17
Weakness: CWE-362

Description

Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. When building a UFO packet with MSG_MORE __ip_append_data() calls ip_ufo_append_data() to append. However in between two send() calls, the append path can be switched from UFO to non-UFO one, which leads to a memory corruption. In case UFO packet lengths exceeds MTU, copy = maxfraglen - skb->len becomes negative on the non-UFO path and the branch to allocate new skb is taken. This triggers fragmentation and computation of fraggap = skb_prev->len - maxfraglen. Fraggap can exceed MTU, causing copy = datalen - transhdrlen - fraggap to become negative. Subsequently skb_copy_and_csum_bits() writes out-of-bounds. A similar issue is present in IPv6 code. The bug was introduced in e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") on Oct 18 2005.

Affected products

Linux kernel: from 2.6.15 before 3.10.108; from 3.11 before 3.16.47; from 3.17 before 3.18.65; from 3.19 before 4.4.82; from 4.5 before 4.9.43; from 4.10 before 4.12.7 — fixed in 3.10.108, 3.16.47, 3.18.65, 4.12.7, 4.4.82, 4.9.43

How to fix

Upgrade to a fixed version: Linux kernel 3.10.108, 3.16.47, 3.18.65, 4.12.7. Check the vendor advisory for mitigations.

References

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