CVE-2023-36811

Archive spoofing via unchecked TAM authentication

Published Aug 30, 2023 · Updated Feb 13, 2025

Improper cryptographic verification in Borg before 1.2.5 allows local users with repository write access to spoof backup archives. Archive loading and repair paths unpack archive metadata without requiring or validating its TAM authentication tag. Exploitation requires both insertion of headerless files into a backup and write access to its repository; forged archives can trigger indirect backup-data loss, but cannot expose plaintext or invalidate existing archives.

CVSS severity4.7
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper cryptographic verification in Borg before 1.2.5 allows local users with repository write access to spoof backup archives. Archive loading and repair paths unpack archive metadata without requiring or validating its TAM authentication tag. Exploitation requires both insertion of headerless files into a backup and write access to its repository; forged archives can trigger indirect backup-data loss, but cannot expose plaintext or invalidate existing archives.

The record

CVE
CVE-2023-36811
Published
Aug 30, 2023
Updated
Feb 13, 2025
Vendor
BorgBackup
Product
Borg
Classifications
CWE-347, T1565.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=< 1.2.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

BorgBackup · Borgversion=< 1.2.5

Published CVSS scores

4.7GitHub CNACVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/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.

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No observations available

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

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1565.001Stored Data Manipulation

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

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Your stack

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