// For flags

CVE-2018-20969

patch: do_ed_script in pch.c does not block strings beginning with a ! character

Severity Score

7.8
*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

2
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

do_ed_script in pch.c in GNU patch through 2.7.6 does not block strings beginning with a ! character. NOTE: this is the same commit as for CVE-2019-13638, but the ! syntax is specific to ed, and is unrelated to a shell metacharacter.

La función do_ed_script en el archivo pch.c en el parche GNU versiones hasta 2.7.6 no bloquea cadenas que comienzan con un carácter !. NOTA: este es el mismo commit para CVE-2019-13638, pero la sintaxis ! es específica para ed y no está relacionada con un metacarácter de shell.

A flaw was found in GNU patch through version 2.7.6. Strings beginning with a exclamation mark are not blocked by default. When ed receives an exclamation mark-prefixed command line argument, the argument is executed as a shell command. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

The patch program applies diff files to originals. The diff command is used to compare an original to a changed file. Diff lists the changes made to the file. A person who has the original file can then use the patch command with the diff file to add the changes to their original file. Issues addressed include a code execution vulnerability.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2019-08-15 CVE Reserved
  • 2019-08-16 CVE Published
  • 2019-08-16 First Exploit
  • 2024-08-05 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Gnu
Search vendor "Gnu"
 Patch
Search vendor "Gnu" for product "Patch"
 <= 2.7.6
Search vendor "Gnu" for product "Patch" and version " <= 2.7.6"
-
Affected