CyberSecBulletin
CVE-2022-23521NVD status: Modified

git: Integer Overflow or Wraparound

Published Updated By the CyberSecBulletin desk

CVE-2022-23521 is a critical-severity integer overflow or wraparound vulnerability in git, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected git versions: < 2.30.7; >= 2.31.0, < 2.31.6; >= 2.32.0, < 2.32.5, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 56.3% chance of exploitation within 30 days, which is in the top 0.93% of all scored CVEs.

Patch now

Exploitation in the next 30 days is more likely than not, according to EPSS.

What to do

  1. Check which version of git you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Gitgit< 2.30.7; >= 2.31.0, < 2.31.6; >= 2.32.0, < 2.32.5; >= 2.33.0, < 2.33.6; >= 2.34.0, < 2.34.6; >= 2.35.0, < 2.35.6; >= 2.36.0, < 2.36.4; >= 2.37.0, < 2.37.5; and 2 more rangesNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalCNA (github.com)
CVSS 3.19.8CriticalNVD

Official description

Git is distributed revision control system. gitattributes are a mechanism to allow defining attributes for paths. These attributes can be defined by adding a `.gitattributes` file to the repository, which contains a set of file patterns and the attributes that should be set for paths matching this pattern. When parsing gitattributes, multiple integer overflows can occur when there is a huge number of path patterns, a huge number of attributes for a single pattern, or when the declared attribute names are huge. These overflows can be triggered via a crafted `.gitattributes` file that may be part of the commit history. Git silently splits lines longer than 2KB when parsing gitattributes from a file, but not when parsing them from the index. Consequentially, the failure mode depends on whether the file exists in the working tree, the index or both. This integer overflow can result in arbitrary heap reads and writes, which may result in remote code execution. The problem has been patched in the versions published on 2023-01-17, going back to v2.30.7. Users are advised to upgrade. There are no known workarounds for this issue.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How developers prevent this class of flaw

  • Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

More Integer Overflow or Wraparound vulnerabilities (CWE-190)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Patches and release notes

Other vulnerabilities in git

All git vulnerabilities

Recent Integer Overflow or Wraparound vulnerabilities

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