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CVE-2026-41676: Rust-Openssl Project Rust-Openssl Out of Bounds Write (CVSS 7.2)

CVE-2026-41676 is a high severity out of bounds write in Rust-Openssl Project Rust-Openssl with a CVSS score of 7.2. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Jul 15, 2026

Quick answer

Direct answer

CVE-2026-41676 is a high severity out of bounds write in Rust-Openssl Project Rust-Openssl with a CVSS score of 7.2. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
7.2HIGH
EPSS probability
0.29%
Higher than 20 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:N)Network: reachable remotely
Attack complexity (AC:L)Low complexity
Attack requirements (AT:P)Attack requirements present
Privileges required (PR:N)No privileges required
User interaction (UI:N)No user interaction
Confidentiality (VC:H)High confidentiality impact
Integrity (VI:H)High integrity impact
Availability (VA:H)High availability impact

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

About Rust-Openssl Project Rust-Openssl

CVE-2026-41676 affects Rust-Openssl Project Rust-Openssl, a product from Rust-Openssl Project. Before acting, confirm where Rust-Openssl Project Rust-Openssl runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.27 to before 0.10.78, Deriver::derive (and PkeyCtxRef::derive) sets len = buf.len() and passes it as the in/out length to EVP_PKEY_derive, relying on OpenSSL to honor it. On OpenSSL 1.1.x, X25519, X448, DH and HKDF-extract ignore the incoming *keylen, unconditionally writing the full shared secret (32/56/prime-size bytes). A caller passing a short slice gets a heap/stack overflow from safe code. OpenSSL 3.x providers do check, so this only impacts older OpenSSL. This vulnerability is fixed in 0.10.78.

The weakness class is Out of Bounds Write. The program writes past the end of a buffer, a common path to code execution.

Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductRust-Openssl Project Rust-Openssl
Affected versionsRust-Openssl from 0.9.27 before 0.10.78
PublishedApr 24, 2026
Last modifiedJul 15, 2026
Added to CISA KEVNot listed
Assigning CNAsecurity-advisories@github.com

How to detect it

  • Inventory every instance of Rust-Openssl Project Rust-Openssl and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Rust-Openssl Project Rust-Openssl named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Rust-Openssl Project Rust-Openssl to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-41676 is a high severity out of bounds write in Rust-Openssl Project Rust-Openssl with a CVSS score of 7.2. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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