VYPR
← All advisories
Unrated severityNVD Advisory· Published Feb 8, 2021· Updated Aug 3, 2024

CVE-2021-26220

CVE-2021-26220

Description

The ezxml_toxml function in ezxml 0.8.6 and earlier is vulnerable to OOB write when opening XML file after exhausting the memory pool.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

ezxml 0.8.6 and earlier has an out-of-bounds write in ezxml_toxml due to incorrect malloc error handling, leading to memory corruption or crash.

Vulnerability

The ezxml_toxml function in ezxml 0.8.6 and earlier is vulnerable to an out-of-bounds (OOB) write when opening an XML file after exhausting the memory pool. The vulnerability exists because the return value of malloc on line 750 of ezxml.c is not checked for NULL; if memory allocation fails, a write to a near-NULL address can occur [1]. The issue is triggered during XML file parsing, which allocates internal buffers of size EZXML_BUFSIZE (1024 bytes).

Exploitation

An attacker can exploit this vulnerability by providing a crafted XML file that causes memory exhaustion during parsing. This can be done locally (e.g., by opening a malicious file) or remotely if the application accepts XML files from external sources [1]. The attacker does not require authentication if the application opens files from untrusted sources. The memory exhaustion leads to malloc returning NULL, and the subsequent string copy operation overwrites memory near address zero.

Impact

Successful exploitation can result in a segmentation fault (crash) or, in environments with limited memory protection (e.g., embedded systems), a near-NULL pointer overwrite. This could corrupt critical data structures or device configuration stored in low memory areas, potentially leading to arbitrary behavior or denial of service [1].

Mitigation

As of the publication date (2021-02-08), no official patch has been released for this vulnerability. Users of ezxml 0.8.6 and earlier should avoid processing untrusted XML files or apply memory allocation error handling similar to the recommendations in ERR33-C [1]. The issue is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

References
  1. ezXML / Bugs / #23 Out-of-bounds write caused by incorrect error handling of malloc in ezxml_new (ezxml.c:750)

AI Insight generated on May 27, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

59

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

1

News mentions

0

No linked articles in our index yet.