What is CVE-2026-43500?A high-severity flaw in Linux kernel, explained.
CVE-2026-43500 is a high-severity flaw (CVSS 7.8) in Linux kernel, published on 11 May 2026. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 94%. If you run an affected version, plan in the vendor’s fix.
Published 11 May 2026. Record last updated 24 August 2026. We keep this page's data up to date.
What is CVE-2026-43500? In plain terms.
An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.
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.
What kind of flaw is it?
- CWE-123Write-what-where Condition
- CWE-787Out-of-bounds Write
How an attack on it works
Read straight from its severity rating, translated out of the shorthand.
- Where an attacker can beAlready on the device
- How hard it is to pull offEasy: no special conditions
- Login needed firstAn ordinary user account
- Does someone have to clickNo, nobody has to do anything
- What an attacker getsCan read data, change data and take it offline
Severity vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is CVE-2026-43500 being exploited? Not that we know of.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 94%. That can change at any time, which is why we keep watching.
Timeline
- Published
- Exploit likelihood jumped
- Record last updated
- Exploit likelihood fell
CVE-2026-43500 scores 70. Action: Patch now.
We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:
- Evidence it is being exploitedBiggest factor
- How severe it isStrong factor
- How widely exposed it isKey context
- Real threat activity around itKey context
85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.
When CVE-2026-43500 matches software you track, it lands in your list with its score and the reasons behind it.
See your own ranked list →Who is affected by CVE-2026-43500? One product.
The published record lists 1 product from 1 vendor. Versions are shown as published: "after 5.3 to before 6.18.29" means every version up to, but not including, 6.18.29. If you run one of these, check your version, then go to the fix below.
- Operating system
Linux kernel
by Linux
Affected versions5.3-rc75.3-rc8after 5.3 to before 6.18.295.36.19 to before 7.0.67.1-rc17.1-rc2
How do I fix CVE-2026-43500? Four steps.
- Check whether you run itCompare your versions with the affected products above. Not sure what you run? EdgeProtect can work it out from your public website, or you can pick it from a list.
- Apply the vendor’s fixInstall the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
- If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
- Keep an eye on itTrack the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.
Does CVE-2026-43500 affect you? We'll keep checking.
Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.
- Tell us what you runPick your software from a list, or let us work it out from your website.
- We match it to every flawOver 400,000 published flaws, checked against your list.
- Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
- Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
Free plan, no card needed. Nothing to install.
1 new flaw affects software Acme tracks
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet ha...
- Matched to
- Linux kernel on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
CVE-2026-43500 is a high-severity flaw in Linux kernel, published on 11 May 2026. An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.
It scores 7.8 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2026-43500 is 70 out of 100, which is High. Its action is "Patch now". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 94%. That can change at any time, which is why we keep watching.
For Linux kernel: 5.3-rc7, 5.3-rc8, after 5.3 to before 6.18.29, 5.3, 6.19 to before 7.0.6, 7.1-rc1 and 1 more.
Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.