Integer Overflow or Wraparound Affecting perf6.18-debuginfo package, versions <1:6.18.16-18.222.amzn2023
Threat Intelligence
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Start learning- Snyk IDSNYK-AMZN2023-PERF618DEBUGINFO-16740923
- published18 May 2026
- disclosed6 May 2026
Introduced: 6 May 2026
NewCVE-2026-43254 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 perf6.18-debuginfo to version 1:6.18.16-18.222.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1711.
NVD Description
Note: Versions mentioned in the description apply only to the upstream perf6.18-debuginfo package and not the perf6.18-debuginfo package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
ovpn: tcp - fix packet extraction from stream
When processing TCP stream data in ovpn_tcp_recv, we receive large cloned skbs from __strp_rcv that may contain multiple coalesced packets. The current implementation has two bugs:
Header offset overflow: Using pskb_pull with large offsets on coalesced skbs causes skb->data - skb->head to exceed the u16 storage of skb->network_header. This causes skb_reset_network_header to fail on the inner decapsulated packet, resulting in packet drops.
Unaligned protocol headers: Extracting packets from arbitrary positions within the coalesced TCP stream provides no alignment guarantees for the packet data causing performance penalties on architectures without efficient unaligned access. Additionally, openvpn's 2-byte length prefix on TCP packets causes the subsequent 4-byte opcode and packet ID fields to be inherently misaligned.
Fix both issues by allocating a new skb for each openvpn packet and using skb_copy_bits to extract only the packet content into the new buffer, skipping the 2-byte length prefix. Also, check the length before invoking the function that performs the allocation to avoid creating an invalid skb.
If the packet has to be forwarded to userspace the 2-byte prefix can be pushed to the head safely, without misalignment.
As a side effect, this approach also avoids the expensive linearization that pskb_pull triggers on cloned skbs with page fragments. In testing, this resulted in TCP throughput improvements of up to 74%.