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Vulnerabilities

Security incident · GHSA-494m-4556-wf5p

imgproxy has out-of-bounds heap read/write in ICO loader BMP header reconstruction that allows unauthenticated remote worker crash

Published Oct 30, 2026 · catalog updated Nov 5, 2026 · imgproxy has out-of-bounds heap

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Open the advisory

Exploitation likelihood is not on this record for GHSA-494m-4556-wf5p. A missing EPSS score is not a low risk. Compare imgproxy has out-of-bounds heap with the linked advisory before you change production.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (imgproxy has out-of-bounds heap).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Awaiting synchronization with FIRST
Remediation
Advisory link
Affected products
Go github.com/imgproxy/imgproxy/v3

### Summary Out-of-bounds heap write in imgproxy's ICO loader ( ): when the ICO entry's image data buffer is small, the loader's BMP-header-reconstruction writes land past the allocation, corrupting the size field of the following heap chunk. The worker then aborts deterministically (glibc → SIGABRT → Go panic, exit code 2). ### Details In in , after the ICO entry's image data is read into a heap buffer of bytes, the loader reconstructs a BMP file header in front of it using fields read from the ICO's internal BITMAPINFOHEADER: With a crafted entry declaring a tiny (e.g. 1 byte), all of these reads (offsets +8, +14, +32) go past the allocation, and the reconstructed-header writes land past the end of the buffer — specifically a 32-bit -derived value at , overwriting the LSBs of the size field of the physically following heap chunk. The corrupted size is always and, in cgo thread arenas, the bit lands in the position of the corrupted word such that the next of the victim deterministically takes glibc's abort path, killing the worker. Depending on heap state, the worker returns 500 for the triggering request and aborts on the corrupted chunk's free; in observed production geometry it dies on the same request (exit code 2). ### PoC ### Impact Out-of-bounds write; demonstrated impact is denial of service (worker crash per crafted request). Any imgproxy deployment from the 3.3.x ICO-support series through v4.0.15 (latest at time of report) that processes attacker-supplied images.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Go github.com/imgproxy/imgproxy/v33.3.0 → 4.0.17

How to fix GHSA-494m-4556-wf5p

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for GHSA-494m-4556-wf5p. A missing EPSS score is not a low risk. Compare imgproxy has out-of-bounds heap with the linked advisory before you change production.

Which versions are affected?

Compare what you have installed with 3.3.0 → 4.0.17. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-125: Out-of-bounds Read; CWE-787: Out-of-bounds Write. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 30, 2026 · GitHub Advisory Database

    Detected

    ### Summary Out-of-bounds heap write in imgproxy's ICO loader ( ): when the ICO entry's image data buffer is small, the loader's BMP-header-reconstruction writes land past the allocation, corrupting the size field of the following heap chunk. The worker then aborts deterministically (glibc → SIGABRT → Go panic, exit code 2). ### Details In in , after the ICO entry's image data is read into a heap

  2. Oct 30, 2026 · GitHub Advisory Database

    Fix available

    github.com/imgproxy/imgproxy/v3 fixed in 4.0.17

  3. Oct 30, 2026 · GitHub Advisory Database

    Fix available

    github.com/imgproxy/imgproxy/v3 fixed in 4.0.17

  4. Oct 30, 2026 · GitHub Advisory Database

    Updated

    ### Summary Out-of-bounds heap write in imgproxy's ICO loader ( ): when the ICO entry's image data buffer is small, the loader's BMP-header-reconstruction writes land past the allocation, corrupting the size field of the following heap chunk. The worker then aborts deterministically (glibc → SIGABRT → Go panic, exit code 2). ### Details In in , after the ICO entry's image data is read into a heap

  5. Nov 5, 2026 · Go Vulnerability Database

    Updated

    ### Summary Out-of-bounds heap write in imgproxy's ICO loader ( ): when the ICO entry's image data buffer is small, the loader's BMP-header-reconstruction writes land past the allocation, corrupting the size field of the following heap chunk. The worker then aborts deterministically (glibc → SIGABRT → Go panic, exit code 2). ### Details In in , after the ICO entry's image data is read into a heap

Sources

  • GitHub Advisory DatabasePackage advisoryGHSA-494m-4556-wf5p

    GitHub Advisory Database record mirrored by OSV.

    github.com
  • Go Vulnerability DatabasePackage advisoryGHSA-494m-4556-wf5p

    imgproxy has out-of-bounds heap read/write in ICO loader BMP header reconstruction that allows unauthenticated remote worker crash

    osv.dev
  • OpenSSF OSV / OSV ScannerPackage advisoryGHSA-494m-4556-wf5p

    imgproxy has out-of-bounds heap read/write in ICO loader BMP header reconstruction that allows unauthenticated remote worker crash

    osv.dev

References

Freshness

Last verified in this catalog Nov 5, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Go Vulnerability DatabaseNov 6, 2026
  • GitHub Advisory DatabaseNov 2, 2026
  • OpenSSF OSV / OSV ScannerNov 2, 2026