Common Weakness Enumeration

CWE-134

Use of Externally-Controlled Format String

The product uses a function that accepts a format string as an argument, but the format string originates from an external source.

CVE-2026-6539 (GCVE-0-2026-6539)

Vulnerability from cvelistv5 – Published: 2026-04-30 20:31 – Updated: 2026-05-01 14:21
VLAI
Title
Notepad++ 8.9.3 Format String Injection via nativeLang.xml
Summary
Notepad++ 8.9.3 contains a format string injection vulnerability in the Find Results panel handler that allows attackers to cause denial of service and information disclosure by crafting a malicious nativeLang.xml language pack file. Attackers can distribute a poisoned language pack through community channels that triggers format string interpretation when a user performs search operations, leading to access violations and potential leakage of stack or register contents.
Severity
4.6 (Medium)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
4.4 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-134 - Use of Externally Controlled Format String
Assigner
References
Impacted products
Vendor Product Version
Notepad++ Notepad++ Affected: 0 , < 8.9.4 (semver)
Create a notification for this product.
Credits
Hazley Samsudin
Show details on NVD website
To clipboard 

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CVE-2026-6843 (GCVE-0-2026-6843)

Vulnerability from cvelistv5 – Published: 2026-04-22 08:30 – Updated: 2026-04-22 12:04
VLAI
Title
Nano: nano: format string vulnerability leads to denial of service
Summary
A flaw was found in nano. A local user could exploit a format string vulnerability in the `statusline()` function. By creating a directory with a name containing `printf` specifiers, the application attempts to display this name, leading to a segmentation fault (SEGV). This results in a Denial of Service (DoS) for the `nano` application.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-134 - Use of Externally-Controlled Format String
Assigner
References
URL Tags
https://access.redhat.com/security/cve/CVE-2026-6843 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2460017 issue-trackingx_refsource_REDHAT
Impacted products
Date Public
2026-04-13 00:00
Credits
Red Hat would like to thank Michał Majchrowicz, Marcin Wyczechowski (AFINE Team) for reporting this issue.
Show details on NVD website
To clipboard 

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CVE-2026-7835 (GCVE-0-2026-7835)

Vulnerability from cvelistv5 – Published: 2026-05-21 07:35 – Updated: 2026-05-21 12:14
VLAI
Title
Format string argument mismatch
Summary
A format string argument mismatch in Netatalk 3.0.3 through 4.4.2 allows a remote authenticated attacker to cause a minor denial of service via crafted input that triggers incorrect format string processing.
Severity
3.1 (Low)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-134 - Use of Externally-Controlled Format String
Assigner
References
Impacted products
Vendor Product Version
Netatalk Netatalk Affected: 3.0.3 , ≤ 4.4.2 (semver)
Unaffected: 4.5.0 (semver)
Create a notification for this product.
Date Public
2026-05-13 00:00
Credits
Arjun Basnet from Securin
Show details on NVD website
To clipboard 

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Mitigation

Phase: Requirements

Description:

  • Choose a language that is not subject to this flaw.
Mitigation

Phase: Implementation

Description:

  • Ensure that all format string functions are passed a static string which cannot be controlled by the user, and that the proper number of arguments are always sent to that function as well. If at all possible, use functions that do not support the %n operator in format strings. [REF-116] [REF-117]
Mitigation

Phase: Build and Compilation

Description:

  • Run compilers and linkers with high warning levels, since they may detect incorrect usage.
CAPEC-135: Format String Injection

An adversary includes formatting characters in a string input field on the target application. Most applications assume that users will provide static text and may respond unpredictably to the presence of formatting character. For example, in certain functions of the C programming languages such as printf, the formatting character %s will print the contents of a memory location expecting this location to identify a string and the formatting character %n prints the number of DWORD written in the memory. An adversary can use this to read or write to memory locations or files, or simply to manipulate the value of the resulting text in unexpected ways. Reading or writing memory may result in program crashes and writing memory could result in the execution of arbitrary code if the adversary can write to the program stack.

CAPEC-67: String Format Overflow in syslog()

This attack targets applications and software that uses the syslog() function insecurely. If an application does not explicitely use a format string parameter in a call to syslog(), user input can be placed in the format string parameter leading to a format string injection attack. Adversaries can then inject malicious format string commands into the function call leading to a buffer overflow. There are many reported software vulnerabilities with the root cause being a misuse of the syslog() function.

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