CVE-2026-43336Network attack vector

Cryptographic key disclosure via uncleared ChaCha state

Published May 8, 2026 · Updated May 8, 2026

Information disclosure in the Linux Kernel ChaCha implementation allows remote attackers to recover cryptographic keys through network traffic. The chacha_permute function leaves the invertible permuted_state array on the kernel stack without zeroizing it, retaining the original state and key. A network-facing ChaCha user such as a configured IPsec or WireGuard endpoint must process attacker-supplied traffic; the flaw supplies no write or service-interruption primitive.

CVSS severity7.5
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in the Linux Kernel ChaCha implementation allows remote attackers to recover cryptographic keys through network traffic. The chacha_permute function leaves the invertible permuted_state array on the kernel stack without zeroizing it, retaining the original state and key. A network-facing ChaCha user such as a configured IPsec or WireGuard endpoint must process attacker-supplied traffic; the flaw supplies no write or service-interruption primitive.

The record

CVE
CVE-2026-43336
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.2
  2. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <066c760acead1fb743bae294dbd89f479ae43b9b
  3. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <1933249263c3a98df79992f61a566476e4163bcc
  4. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <1d761e5a7340c46479fb2399598f331e4fe2c633
  5. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <91999af43ca2125e3b2c18fcfc02912ada02efc3
  6. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <b416a4245f04a450c67a13e6d96056c37c5b33fe
  7. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <bd62d9b44464a6c20a34a74068e7a784d0afa04a
  8. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <e5046823f8fa3677341b541a25af2fcb99a5b1e0
  9. Affected versionversion=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <e90ee961af515a484f091678ce58a4c3f7b73b02

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.2; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <066c760acead1fb743bae294dbd89f479ae43b9b; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <1933249263c3a98df79992f61a566476e4163bcc; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <1d761e5a7340c46479fb2399598f331e4fe2c633; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <91999af43ca2125e3b2c18fcfc02912ada02efc3; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <b416a4245f04a450c67a13e6d96056c37c5b33fe; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <bd62d9b44464a6c20a34a74068e7a784d0afa04a; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <e5046823f8fa3677341b541a25af2fcb99a5b1e0; version=c08d0e647305c3f8f640010a56c9e4bafb9488d3 <e90ee961af515a484f091678ce58a4c3f7b73b02

Published CVSS scores

7.5Linux kernel.org CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
4.7Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

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