Stack-based Buffer OverflowWeakness · CWE-121

CVE-2025-34457

HIGH · 8.7 CVSS v4.0 Published 2025-12-22
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
96/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
wb2osz/direwolf (Dire Wolf) versions up to and including 1.8, prior to commit 694c954, contain a stack-based buffer overflow vulnerability in the function kiss_rec_byte() located in src/kiss_frame.c. When processing crafted KISS frames that reach the maximum allowed frame length (MAX_KISS_LEN), the function appends a terminating FEND byte without reserving sufficient space in the stack buffer. This results in an out-of-bounds write followed by an out-of-bounds read during the subsequent call to kiss_unwrap(), leading to stack memory corruption or application crashes. This vulnerability may allow remote unauthenticated attackers to trigger a denial-of-service condition.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-121

Data overflows a fixed-size buffer allocated on the stack, overwriting adjacent stack memory — including saved return addresses — which is the classic route to redirecting execution into attacker-supplied code. Crafted input is all it takes. Remediation is strict length checks, safe bounded string and memory functions, and modern stack-protection mitigations.

General guidance for the stack-based buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix Moderate confidence

Latest version from GitHub after commit 694c954 (post-1.8 release)

  1. 1. Check the current installed version of direwolf by running `direwolf --version` or reviewing your package manager's installed version
  2. 2. Navigate to the official direwolf GitHub repository at https://github.com/wb2osz/direwolf
  3. 3. Obtain the source code after commit 694c954. Either clone the repository with `git clone https://github.com/wb2osz/direwolf.git` and checkout the latest commit, or download the most recent release tarball
  4. 4. Rebuild direwolf from source following the build instructions in the README (typically `make`, `sudo make install`)
  5. 5. Verify the installation by running `direwolf --version` and confirm the version includes the security fix
  6. 6. Restart any services or applications that use direwolf

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-34457 in production — separate from our analysis above.

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