CVE-2026-43284: Linux Kernel vulnerability (CVSS 8.8)

Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data().

CVSS 3.1 breakdown

Attack vectorLocal

Attack complexityLow

Privileges requiredLow

User interactionNone

ScopeChanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

Linux Kernel≥ 4.11 < 5.10.255 · ≥ 5.12 < 5.15.205 · ≥ 5.16 < 6.1.171 · ≥ 6.13 < 6.18.28

Remediation

Fixed in

Linux Kernel≥ 5.10.255

Patch & vendor advisories

References

and 50 more references

Related CVEs

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Frequently asked

Is CVE-2026-43284 being actively exploited?

CVE-2026-43284 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 2.47%.

How severe is CVE-2026-43284?

CVE-2026-43284 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 2.47% probability of exploitation.

Which products are affected by CVE-2026-43284?

Affected products include Linux Kernel.

How do I fix CVE-2026-43284?

Upgrade affected software to a fixed version, for example Linux Kernel 5.10.255 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

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