CVE-2026-43500linux Out-of-Bounds Write
kernel: "Dirty Frag" RxRPC variant is a new universal Local Privilege Escalation (LPE) vulnerability in the Linux kernel
Published May 12, 2026 · Updated Oct 20, 2026 · Also known as DEBIAN-CVE-2026-43500, TR-26-0576, UBUNTU-CVE-2026-43500
Key Facts
Patch immediately- CVE-2026-43500 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting linux-aws-6.18 (chainguard), linux-azure-6.18 (chainguard), linux-gcp-6.18 (chainguard) and 22 more products.
- It is exploited in the wild, listed in Industry KEV feed since May 11, 2026. A public exploit is reported by tracking sources, but no code link is listed yet.
- EPSS estimates a 94% probability of exploitation in the next 30 days.
- Fixed versions are available, including bpftool 6.1.175-2.ph5, bpftool 6.12.92-1.ph5, bpftool 7.7.0+6.17.0-35.35.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v3.1
7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
94%
Higher than 99.8% of all scored CVEs
Exploit maturity
Exploited (KEV)
ATLAS score
82/100
Publication score, see How it works
Exploitation Verdict
KEV listed
May 11, 2026
-1 days after publication
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Exploited (KEV)
Public exploit code
3
Proof-of-concept links
In-the-wild evidence
2
Reports of active use
Advisories And Exploit References
- advisoryhttps://www.cve.org/CVERecord?id=CVE-2026-43500
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-43500
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2026-43500
- advisoryhttps://ubuntu.com/security/CVE-2026-43500
- advisoryhttps://git.kernel.org/stable/c/1381b021bf886b793fa5ffb895a8efae7ba0318f
- advisoryhttps://git.kernel.org/stable/c/2e121c53b581e40397ae08090a7af4ed10781fbc
Description
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | May 11, 2026 | n/a | Not reported |
Affected Products
4,917 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| linux-aws-6.18chainguard | See advisory | 6.18.31-r0 |
| linux-azure-6.18chainguard | See advisory | 6.18.31-r0 |
| linux-gcp-6.18chainguard | See advisory | 6.18.31-r0 |
| linux-qemu-6.18chainguard | See advisory | 6.18.31-r0 |
| linux-qemu-melangechainguard | See advisory | 6.18.31-r0 |
Patched Releases
bpftool
6.1.175-2.ph5, 6.12.92-1.ph5, 7.7.0+6.17.0-35.35, 7.7.0+7.0.0-22.22, NA
cluster-md-kmp-64kb
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
cluster-md-kmp-azure
6.12.0-160000.30.1
cluster-md-kmp-default
5.14.21-150400.24.219.1, 5.14.21-150500.55.163.1, 5.14.21-150500.55.166.1, 6.12.0-160000.30.1, 6.4.0-150600.23.103.1
cluster-md-kmp-rt
6.12.0-160000.30.1, 6.4.0-150700.7.44.1, 6.4.0-150700.7.51.1
dlm-kmp-64kb
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dlm-kmp-azure
6.12.0-160000.30.1
dlm-kmp-default
5.14.21-150400.24.219.1, 5.14.21-150500.55.163.1, 5.14.21-150500.55.166.1, 6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dlm-kmp-rt
6.12.0-160000.30.1, 6.4.0-150700.7.44.1, 6.4.0-150700.7.51.1
dtb-allwinner
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-altera
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-amazon
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-amd
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-amlogic
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-apm
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-apple
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-arm
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-broadcom
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-cavium
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-exynos
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-freescale
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-hisilicon
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-lg
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-marvell
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
dtb-mediatek
6.12.0-160000.30.1, 6.4.0-150600.23.103.1
Timeline
Added to Industry KEV feed
May 11, 2026
Publicly disclosed
May 12, 2026
Last updated
Oct 20, 2026
Weakness Type
- CWE-123 Write-what-where Condition
- CWE-787 Out-of-bounds Write
References
- advisorycve.org · CVERecord
- advisorynvd.nist.gov · CVE-2026-43500
- advisorysecurity-tracker.debian.org · CVE-2026-43500
- advisoryubuntu.com · CVE-2026-43500
- advisorygit.kernel.org · 1381b02
FAQ
Common Questions.
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…
Affected: linux-aws-6.18 (chainguard); linux-azure-6.18 (chainguard); linux-gcp-6.18 (chainguard), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since May 11, 2026.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
A public exploit is reported by tracking sources, but no code link is listed yet.
Fixed versions are available, including bpftool 6.1.175-2.ph5, bpftool 6.12.92-1.ph5, bpftool 7.7.0+6.17.0-35.35.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2026-43500 On Your Attack Surface?
Brandefense matches it against the products discovered on your perimeter and opens a finding the day a CVE like this is listed.
Request A Demo