CVE Vulnerabilities

CVE-2021-20266

Out-of-bounds Read

Published: Apr 30, 2021 | Modified: Nov 07, 2023
CVSS 3.x
4.9
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
4 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P
RedHat/V2
RedHat/V3
3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Ubuntu
LOW

A flaw was found in RPMs hdrblobInit() in lib/header.c. This flaw allows an attacker who can modify the rpmdb to cause an out-of-bounds read. The highest threat from this vulnerability is to system availability.

Weakness

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

Affected Software

Name Vendor Start Version End Version
Rpm Rpm * 4.16.1.3 (excluding)
Red Hat Enterprise Linux 8 RedHat rpm-0:4.14.3-19.el8 *
Red Hat Enterprise Linux 8 RedHat rpm-0:4.14.3-19.el8 *
Rpm Ubuntu bionic *
Rpm Ubuntu esm-apps/bionic *
Rpm Ubuntu esm-apps/focal *
Rpm Ubuntu focal *
Rpm Ubuntu groovy *
Rpm Ubuntu hirsute *
Rpm Ubuntu impish *
Rpm Ubuntu precise/esm *
Rpm Ubuntu trusty *
Rpm Ubuntu upstream *
Rpm Ubuntu xenial *

Potential Mitigations

  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

References