GHSA-7C26-995W-6F47
Vulnerability from github – Published: 2026-07-29 15:19 – Updated: 2026-07-29 15:19Summary
Description
A PostScript-interpreter-driven Denial of Service (CWE-1325) vulnerability in veraPDF allows a remote attacker to exhaust validator memory or CPU by submitting a PDF whose Type 1 font /FontFile is a font program containing attacker-supplied PostScript. veraPDF's Type 1 font program parser dispatches every cleartext token through a hardcoded operator allow-list whose members include the unbounded array N allocation operator and the for control operator with no zero-increment guard. This affects all current versions of veraPDF-parser.
Details
The vulnerability resides in veraPDF-parser. Type 1 font program streams referenced from any Type 1 font's /FontDescriptor /FontFile are parsed by Type1FontProgram (veraPDF-parser/src/main/java/org/verapdf/pd/font/type1/Type1FontProgram.java), which extends PSParser. parseFont reads cleartext PostScript tokens until it encounters eexec (which switches into the encrypted private dictionary parser) or end-of-stream. Each non-eexec token is dispatched via toExecute, which gates execution behind a hardcoded allow-list.
The allow-list explicitly admits both ARRAY (Type1FontProgram.java:98) and FOR (Type1FontProgram.java:100). When either keyword passes the gate, operator.execute delegates straight into the generic PSOperator implementation (org.verapdf.parser.postscript.PSOperator, methods array() at PSOperator.java:536-547 and opFor() at PSOperator.java:571-592), which apply no validation:
array NcallsCOSArray.construct(N)followed bynew ArrayList<>(N)(COSArray.java:102), so the underlyingObject[]is allocated up-front. Passing2147483647(Integer.MAX_VALUE) requests a 16 GB backing array on a 64-bit JVM.forrunsfor (long i = initial; i <= limit; i += increment)with no validation ofincrement. Withincrement == 0, the loop never exits.
In addition to the two shared primitives, toExecute introduces a third primitive specific to this code path: when an unknown operator is encountered, it looks the name up in userDict and recursively re-executes the value. There is no visited-set, no recursion-depth cap, and no detection of a cycle. A Type 1 font program that defines a name to itself, such as /loop { loop } def loop, recurses indefinitely on the JVM stack and throws StackOverflowError after ~16,000 frames.
The interpreter is reachable on every Type 1 font validation. GFPDType1Font's constructor unconditionally calls program.parseFont().
Type1FontProgram.parseFont only catches PostScriptException and rewraps it as IOException; it does not catch OutOfMemoryError, StackOverflowError, or wall-clock budget, so any of the three failure modes propagates out of font model construction and aborts the validation worker.
A single payload byte sequence is sufficient. The conventional %!PS-AdobeFont-1.0 header line is treated as a comment and skipped; the parser then begins consuming PostScript tokens, the very first for invocation enters the infinite loop, and the parser never reaches the eexec boundary that would normally end the cleartext section.
Impact
This impacts all current releases of the veraPDF-parser. Successful exploitation requires only that the target validate an attacker-supplied PDF; a single Type 1 font with a malicious /FontFile stream is sufficient.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.30.1"
},
"package": {
"ecosystem": "Maven",
"name": "org.verapdf:parser"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.30.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.31.22"
},
"package": {
"ecosystem": "Maven",
"name": "org.verapdf:parser"
},
"ranges": [
{
"events": [
{
"introduced": "1.31.1"
},
{
"fixed": "1.31.23"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-54081"
],
"database_specific": {
"cwe_ids": [
"CWE-1325"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-29T15:19:04Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "## Summary\n\n**Description**\n\nA PostScript-interpreter-driven Denial of Service (CWE-1325) vulnerability in veraPDF allows a remote attacker to exhaust validator memory or CPU by submitting a PDF whose Type 1 font `/FontFile` is a font program containing attacker-supplied PostScript. veraPDF\u0027s Type 1 font program parser dispatches every cleartext token through a hardcoded operator allow-list whose members include the unbounded `array N` allocation operator and the `for` control operator with no zero-increment guard. This affects all current versions of veraPDF-parser.\n\n## Details\n\nThe vulnerability resides in veraPDF-parser. Type 1 font program streams referenced from any Type 1 font\u0027s `/FontDescriptor /FontFile` are parsed by `Type1FontProgram` (veraPDF-parser/src/main/java/org/verapdf/pd/font/type1/Type1FontProgram.java), which extends `PSParser`. `parseFont` reads cleartext PostScript tokens until it encounters `eexec` (which switches into the encrypted private dictionary parser) or end-of-stream. Each non-`eexec` token is dispatched via `toExecute`, which gates execution behind a hardcoded allow-list.\n\nThe allow-list explicitly admits both `ARRAY` (Type1FontProgram.java:98) and `FOR` (Type1FontProgram.java:100). When either keyword passes the gate, `operator.execute` delegates straight into the generic `PSOperator` implementation (`org.verapdf.parser.postscript.PSOperator`, methods `array()` at PSOperator.java:536-547 and `opFor()` at PSOperator.java:571-592), which apply no validation:\n\n1. `array N` calls `COSArray.construct(N)` followed by `new ArrayList\u003c\u003e(N)` (COSArray.java:102), so the underlying `Object[]` is allocated up-front. Passing `2147483647` (`Integer.MAX_VALUE`) requests a 16 GB backing array on a 64-bit JVM.\n2. `for` runs `for (long i = initial; i \u003c= limit; i += increment)` with no validation of `increment`. With `increment == 0`, the loop never exits.\n\nIn addition to the two shared primitives, `toExecute` introduces a third primitive specific to this code path: when an unknown operator is encountered, it looks the name up in `userDict` and recursively re-executes the value. There is no visited-set, no recursion-depth cap, and no detection of a cycle. A Type 1 font program that defines a name to itself, such as `/loop { loop } def loop`, recurses indefinitely on the JVM stack and throws `StackOverflowError` after ~16,000 frames.\n\nThe interpreter is reachable on every Type 1 font validation. `GFPDType1Font`\u0027s constructor unconditionally calls `program.parseFont()`.\n\n`Type1FontProgram.parseFont` only catches `PostScriptException` and rewraps it as `IOException`; it does not catch `OutOfMemoryError`, `StackOverflowError`, or wall-clock budget, so any of the three failure modes propagates out of font model construction and aborts the validation worker.\n\nA single payload byte sequence is sufficient. The conventional `%!PS-AdobeFont-1.0` header line is treated as a comment and skipped; the parser then begins consuming PostScript tokens, the very first `for` invocation enters the infinite loop, and the parser never reaches the `eexec` boundary that would normally end the cleartext section.\n\n## Impact\n\nThis impacts all current releases of the veraPDF-parser. Successful exploitation requires only that the target validate an attacker-supplied PDF; a single Type 1 font with a malicious `/FontFile` stream is sufficient.",
"id": "GHSA-7c26-995w-6f47",
"modified": "2026-07-29T15:19:04Z",
"published": "2026-07-29T15:19:04Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/veraPDF/veraPDF-parser/security/advisories/GHSA-7c26-995w-6f47"
},
{
"type": "WEB",
"url": "https://github.com/veraPDF/veraPDF-parser/pull/703"
},
{
"type": "WEB",
"url": "https://github.com/veraPDF/veraPDF-parser/commit/73d6ec002b98ce1f3f68640442f8e5d5613c80ce"
},
{
"type": "WEB",
"url": "https://github.com/veraPDF/veraPDF-parser/commit/cb3538607a549d63504299be1088c85ae48605f4"
},
{
"type": "PACKAGE",
"url": "https://github.com/veraPDF/veraPDF-parser"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "veraPDF Parser DoS via PostScript Type 1 Font Programs"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.