CVE-2021-26252Public exploit

Code execution via unchecked page index

Published Feb 24, 2022 · Updated Aug 3, 2024

An out-of-bounds read in HTMLDOC 1.9.15 allows context-dependent attackers to execute code or crash the process via crafted HTML. The pspdf_prepare_page() function dereferences pages[page] without first ensuring that page is between zero and num_pages minus one. A user or automated document workflow must process the crafted HTML as PostScript or PDF; successful exploitation can terminate the converter or execute code in its security context.

CVSS severity7.8
High
EPSS probability0.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds read in HTMLDOC 1.9.15 allows context-dependent attackers to execute code or crash the process via crafted HTML. The pspdf_prepare_page() function dereferences pages[page] without first ensuring that page is between zero and num_pages minus one. A user or automated document workflow must process the crafted HTML as PostScript or PDF; successful exploitation can terminate the converter or execute code in its security context.

The record

CVE
CVE-2021-26252
Published
Feb 24, 2022
Updated
Aug 3, 2024
Vendor
HTMLDOC Project
Product
HTMLDOC
Classifications
CWE-787, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=htmldoc 1.9.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

HTMLDOC Project · HTMLDOCversion=htmldoc 1.9.15

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8CanonicalCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.8SUSECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1204.002Malicious File
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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