Patchfirst
CVE-2026-43500 Public exploit High · 7.8 EPSS 94.1%

rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present

Linux · Linux

Summary

The Linux kernel's rxrpc networking component fails to unshare certain received DATA and RESPONSE packets that carry externally-owned paged fragments before decrypting them in place, so the frag pages are bound directly into the crypto scatter-gather list. An attacker with local access and low privileges could potentially exploit this by sending crafted traffic that leverages shared fragments, with no user interaction required.

Official description · CVE.org

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owned paged fragments (e.g. SKBFL_SHARED_FRAG set by splice() into a UDP socket via __ip_append_data, or a chained skb_has_frag_list()) falls through to the in-place decryption path, which binds the frag pages directly into the AEAD/skcipher SGL via skb_to_sgvec(). Extend the gate to also unshare when skb_has_frag_list() or skb_has_shared_frag() is true. This catches the splice-loopback vector and other externally-shared frag sources while preserving the zero-copy fast path for skbs whose frags are kernel-private (e.g. NIC page_pool RX, GRO). The OOM/trace handling already in place is reused.

Breakdown
73.1 / 100
Exploited
Yes, in VulnCheck KEV
Reports
0
Tactics
0/15

First seen exploited the day it was disclosed. Public exploit code (PoC-in-GitHub) was available 11 days before disclosure.

  1. Public exploit codePoC-in-GitHub11 days before
  2. DisclosedFirst seen exploitedVulnCheck KEV evidenceday 0

techniques

No techniques linked

No ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.

What security researchers reported

Not named in any threat report yet

Also mentioned in 14 community threat pulses (AlienVault OTX)

Weaker evidence

Pulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.

References

9 links, grouped by NVD tag
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