Vulnerability-Lookup

MSRC_CVE-2026-33416

Vulnerability from csaf_microsoft - Published: 2026-03-02 00:00 - Updated: 2026-04-02 01:05

Summary

LIBPNG has use-after-free via pointer aliasing in `png_set_tRNS` and `png_set_PLTE`

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

CVE-2026-33416

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE-416 - Use After Free

None Available There is no fix available for this vulnerability as of now

Vendor Fix 1.6.56-1:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade https://learn.microsoft.com/en-us/azure/azure-lin…

References

URL

Category

	https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self
	https://support.microsoft.com/lifecycle	external
	https://www.first.org/cvss	external
	https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self

JSON

To clipboard

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        "title": "Additional Resources"
      },
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        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
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        "summary": "CVE-2026-33416 LIBPNG has use-after-free via pointer aliasing in `png_set_tRNS` and `png_set_PLTE` - VEX",
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        "name": "Use After Free"
      },
      "notes": [
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          "category": "general",
          "text": "GitHub_M",
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        {
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          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-33416.json"
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      "remediations": [
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            "baseScore": 7.5,
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            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
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            "privilegesRequired": "NONE",
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            "temporalScore": 7.5,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
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            "17084-6",
            "17084-8",
            "17084-3",
            "17084-2",
            "17086-1"
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        }
      ],
      "title": "LIBPNG has use-after-free via pointer aliasing in `png_set_tRNS` and `png_set_PLTE`"
    }
  ]
}

CVE-2026-33416 (GCVE-0-2026-33416)

Vulnerability from cvelistv5 – Published: 2026-03-26 16:48 – Updated: 2026-04-01 03:55

Title

LIBPNG has use-after-free via pointer aliasing in `png_set_tRNS` and `png_set_PLTE`

Summary

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.2.1 through 1.6.55, `png_set_tRNS` and `png_set_PLTE` each alias a heap-allocated buffer between `png_struct` and `png_info`, sharing a single allocation across two structs with independent lifetimes. The `trans_alpha` aliasing has been present since at least libpng 1.0, and the `palette` aliasing since at least 1.2.1. Both affect all prior release lines `png_set_tRNS` sets `png_ptr->trans_alpha = info_ptr->trans_alpha` (256-byte buffer) and `png_set_PLTE` sets `info_ptr->palette = png_ptr->palette` (768-byte buffer). In both cases, calling `png_free_data` (with `PNG_FREE_TRNS` or `PNG_FREE_PLTE`) frees the buffer through `info_ptr` while the corresponding `png_ptr` pointer remains dangling. Subsequent row-transform functions dereference and, in some code paths, write to the freed memory. A second call to `png_set_tRNS` or `png_set_PLTE` has the same effect, because both functions call `png_free_data` internally before reallocating the `info_ptr` buffer. Version 1.6.56 fixes the issue.

Severity ?

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE

CWE-416 - Use After Free

Assigner

GitHub_M

References

URL

Tags

	https://github.com/pnggroup/libpng/security/advis…	x_refsource_CONFIRM
	https://github.com/pnggroup/libpng/pull/824	x_refsource_MISC
	https://github.com/pnggroup/libpng/commit/2301926…	x_refsource_MISC
	https://github.com/pnggroup/libpng/commit/7ea9eea…	x_refsource_MISC
	https://github.com/pnggroup/libpng/commit/a3a2144…	x_refsource_MISC
	https://github.com/pnggroup/libpng/commit/c1b0318…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	pnggroup	libpng	Affected: >= 1.2.1, < 1.6.56

Show details on NVD website

JSON

To clipboard

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      "title": "LIBPNG has use-after-free via pointer aliasing in `png_set_tRNS` and `png_set_PLTE`"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-33416",
    "datePublished": "2026-03-26T16:48:54.174Z",
    "dateReserved": "2026-03-19T17:02:34.172Z",
    "dateUpdated": "2026-04-01T03:55:17.603Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Detection rules are retrieved from Rulezet.

Action not permitted

MSRC_CVE-2026-33416

CVE-2026-33416 (GCVE-0-2026-33416)

Tags

Sightings

Nomenclature