# crypto: pcrypt - Fix handling of MAY_BACKLOG requests

CVE record · `CVE-2026-43493`

- **Identifiers:** `CVE-2026-43493`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **CNA:** Linux
- **Weakness (CWE):** [CWE-390](https://cwe.mitre.org/data/definitions/390.html)
- **Tags:** [CWE-390](https://agentprime.io/advisories/tag/cwe-390.md)
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 19 May 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 19 May 2026, 10:44 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before ae7e95638d956d556d74b9abb9e780d3bd3dcd9e` (git)
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before 1d7f07df450bac3301938fbc4251f2611be4084e` (git)
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before 76641449b28979ebd6c02e9598367e119e385236` (git)
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before 9f1cbca178c03188e201ed175251372149bb25f2` (git)
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before eb34e243df57e32f4c08fa191f3602ea19076276` (git)
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before 77d55bc8675ee851ed639dc9be77325a8024cf67` (git)
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before 46271895ddfb1ba41f89f7e0dffbe9c2bcf7380a` (git)
  - affected: `5a1436beec5744029f3ac90b6fe71a698dcd6155 to before 915b692e6cb723aac658c25eb82c58fd81235110` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.34`
  - unaffected: `before 2.6.34` (semver)
  - unaffected: `5.10.258 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.209 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.175 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.140 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.86 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.27 to 6.18.*, inclusive` (semver)
  - unaffected: `7.0.4 to 7.0.*, inclusive` (semver)
  - unaffected: `7.1 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 9.8 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0068, the 52nd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 19 May 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-43493](https://www.cve.org/CVERecord?id=CVE-2026-43493)
- [NVD: CVE-2026-43493](https://nvd.nist.gov/vuln/detail/CVE-2026-43493)

### References from the CNA

- <https://git.kernel.org/stable/c/ae7e95638d956d556d74b9abb9e780d3bd3dcd9e>
- <https://git.kernel.org/stable/c/1d7f07df450bac3301938fbc4251f2611be4084e>
- <https://git.kernel.org/stable/c/76641449b28979ebd6c02e9598367e119e385236>
- <https://git.kernel.org/stable/c/9f1cbca178c03188e201ed175251372149bb25f2>
- <https://git.kernel.org/stable/c/eb34e243df57e32f4c08fa191f3602ea19076276>
- <https://git.kernel.org/stable/c/77d55bc8675ee851ed639dc9be77325a8024cf67>
- <https://git.kernel.org/stable/c/46271895ddfb1ba41f89f7e0dffbe9c2bcf7380a>
- <https://git.kernel.org/stable/c/915b692e6cb723aac658c25eb82c58fd81235110>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-43493>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-43493/>. Everything for agents: <https://agentprime.io/llms.txt>.