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CVE Record

CVE-2021-28677: An issue was discovered in Pillow before 8.2.0.

An issue was discovered in Pillow before 8.2.0. For EPS data, the readline implementation used in EPSImageFile has to deal with any combination of \r and \n as line endings. It used an accidentally quadratic method of accumulating lines while looking for a line ending. A malicious EPS file could use this to perform a DoS of Pillow in the open phase, before an image was accepted for opening.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Pillow versions before 8.2.0 could be slowed or tied up when opening a specially crafted EPS image. Services that process uploaded or external EPS files could lose worker capacity. The provided sources describe denial of service, not data theft or code execution.

Executive priority

Treat this as a moderate availability risk. It should be fixed promptly on services that process untrusted images, especially customer-facing upload or conversion paths, but the provided evidence does not indicate active exploitation or confidentiality impact.

Technical view

EPSImageFile readline handling used an accidentally quadratic method while processing EPS line endings containing combinations of carriage returns and newlines. A malicious EPS could trigger denial of service during the open phase, before the image was accepted for opening. Upstream fixed this in Pillow 8.2.0.

Likely exposure

Exposure is most likely in Python applications or services using Pillow before 8.2.0 to open untrusted EPS files, including upload pipelines, document conversion, thumbnailing, or batch image processing. The bundle does not provide CPEs or exact downstream package versions.

Exploitation context

The sources support a crafted-file denial-of-service scenario. CISA KEV is false in the bundle, and no cited source states active exploitation. Exploitation would require the vulnerable Pillow code to attempt opening attacker-controlled EPS data.

Researcher notes

The key defect is algorithmic complexity in EPS readline behavior, addressed by Pillow PR 5377 and the 8.2.0 release. The source bundle lacks CVSS, CWE, CPEs, and full downstream version mapping, so validation depends on local dependency and package inventory.

Mitigation direction

  • Upgrade Pillow to 8.2.0 or later where application packaging allows.
  • Apply patched operating-system packages from relevant vendor advisories.
  • Review vendor guidance for affected distro package names and fixed versions.
  • Limit processing of untrusted EPS files until patched.
  • Prioritize internet-facing upload or conversion services first.

Validation and detection

  • Inventory applications and containers for Pillow versions before 8.2.0.
  • Identify workflows that open EPS files from users or external sources.
  • Confirm distro security updates are installed where Pillow is OS-packaged.
  • Verify dependency lockfiles and deployed images contain the patched Pillow version.
  • Check image-processing queues for services that can be stalled by slow opens.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

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0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
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Weakness

CWE details

No CWE listed

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