CyberSecBulletin
CVE-2022-41743NVD status: Modified

NGINX Plus: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-41743 is a high-severity out-of-bounds write vulnerability in NGINX Plus from F5, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions R27-p1, R26-p1 as the first without the flaw, so updating NGINX Plus to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.23% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update NGINX Plus to R27-p1 or R26-p1, whichever matches your release line, or a later version.
  2. Read the advisory on support.f5.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
F5NGINX PlusR27 up to, but not including, R27-p1; R1 up to, but not including, R26-p1R27-p1, R26-p1
F5Nginx Ingress Controller1.9.0 through 1.12.4; 2.0.0 through 2.4.0Not 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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
LowA basic user account is enough.
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:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.0HighCNA (f5.com)
CVSS 3.17.0HighNVD

Official description

NGINX Plus before versions R27 P1 and R26 P1 have a vulnerability in the module ngx_http_hls_module that might allow a local attacker to corrupt NGINX worker memory, resulting in its crash or potential other impact using a specially crafted audio or video file. The issue affects only NGINX Plus when the hls directive is used in the configuration file. Further, the attack is possible only if an attacker can trigger processing of a specially crafted audio or video file with the module ngx_http_hls_module.

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

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in NGINX Plus

All NGINX Plus vulnerabilities

Recent Out-of-bounds Write vulnerabilities

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