dbcve.org
Debian LinuxOperating system · Debian

CVE-2021-41054

HIGH · 7.5 CVSS v3.1 Published 2021-09-13
Fix available
A fix is available. Upgrade to after 0.7.4 or later.
See remediation →
84/100
Remediation priority · High
Public exploit 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
tftpd_file.c in atftp through 0.7.4 has a buffer overflow because buffer-size handling does not properly consider the combination of data, OACK, and other options.

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-120

A fixed-size buffer is filled without checking the length of the incoming data, so it overflows into neighbouring memory. This is the classic overflow attackers use to overwrite return addresses and hijack execution. The fix is strict length checks and safe, bounded string and memory functions.

General guidance for the classic 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 →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 9.0
AtftpApplication
Affected:<= 0.7.4

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
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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
Upgrade available Upgrade to a release after 0.7.4
Vendor patch sourceforge.net →
Recommended fix High confidence

atftp version 0.7.5 or later (or apply vendor patch commit d255bf90834fb45be52decf9bc0b4fb46c90f205 to version 0.7.4)

  1. 1. Identify the current atftp version installed on the system using: dpkg -l | grep atftp or atftp --version
  2. 2. For Debian 9.0 (stretch), check if a fixed package is available in backports or update to a newer Debian release that includes atftp >= 0.7.5
  3. 3. If building from source, obtain atftp source code and apply the fix from commit d255bf90834fb45be52decf9bc0b4fb46c90f205: git checkout d255bf90834fb45be52decf9bc0b4fb46c90f205 or apply the specific code changes in tftpd_file.c related to buffer-size handling for OACK options
  4. 4. Rebuild and reinstall atftp from the patched source
  5. 5. Verify the fix by checking the version: atftp --version (should show 0.7.5 or later with the patch applied)
  6. 6. Test TFTP functionality to ensure the service operates correctly after the update
Caveat Minor: Ensure any TFTP client configurations that rely on specific buffer size behavior are compatible with the corrected implementation

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

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $3,200. Get the upgrade done

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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-2021-41054 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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