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Medium, CVSS 6.5amended

PDFME Affected by Decompression Bomb in FlateDecode Stream Parsing Causes Memory Exhaustion DoS

CVE-2026-82864GHSA-vrqm-gvq7-rrwh

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (@pdfme/pdf-lib 5.5.10), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2026-82864: 0.44% estimated exploitation activity in the next 30 days; percentile 37.89 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary The DecodeStream.ensureBuffer() method in @pdfme/pdf-lib doubles its internal buffer without any upper bound on the decompressed size. A crafted PDF containing a FlateDecode stream with a high compression ratio (decompression bomb) causes unbounded memory allocation during stream decoding, leading to memory exhaustion and denial of service in both server-side (generator) and client-side (UI) contexts. Details The vulnerability exists in the DecodeStream class, which is the base class for all stream decoders including FlateStream (DEFLATE/zlib decompression). Unbounded buffer growth in ensureBuffer() — packages/pdf-lib/src/core/streams/DecodeStream.ts:148-160: The size = 2 loop has no maximum size check. The buffer will continue doubling until the process runs out of memory. Unconditional full decompression in decode() — DecodeStream.ts:139-141: FlateStream.readBlock() calls ensureBuffer() repeatedly during decompression —…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-vrqm-gvq7-rrwh

  2. Revision 1 · created ·

    Published from osv record GHSA-vrqm-gvq7-rrwh

Agent brief

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# Patch Next advisory brief: CVE-2026-82864

Advisory: PDFME Affected by Decompression Bomb in FlateDecode Stream Parsing Causes Memory Exhaustion DoS
IDs: CVE-2026-82864, GHSA-vrqm-gvq7-rrwh
Record: https://patchnext.com/advisories/cve-2026-82864 (revision 2, source checked 26 Oct 2026, 12:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @pdfme/pdf-lib 5.5.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @pdfme/pdf-lib: affected <= 5.5.9; fixed in 5.5.10

## Suggested inspection (read-only)
- `npm ls @pdfme/pdf-lib --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @pdfme/pdf-lib.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-vrqm-gvq7-rrwh (OSV record GHSA-vrqm-gvq7-rrwh lists affected ranges: npm @pdfme/pdf-lib >=0 <5.5.10 (fixed))
- Verified: https://github.com/advisories/GHSA-vrqm-gvq7-rrwh (GitHub-reviewed advisory GHSA-vrqm-gvq7-rrwh lists affected ranges: npm @pdfme/pdf-lib >=0 <=5.5.9)

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