LiveActive security incident?Get immediate response
CVE Record

CVE-2026-25646: LIBPNG has a heap buffer overflow in png_set_quantize

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. Prior to 1.6.55, an out-of-bounds read vulnerability exists in the png_set_quantize() API function. When the function is called with no histogram and the number of colors in the palette is more than twice the maximum supported by the user's display, certain palettes will cause the function to enter into an infinite loop that reads past the end of an internal heap-allocated buffer. The images that trigger this vulnerability are valid per the PNG specification. This vulnerability is fixed in 1.6.55.

HighCVSS 8.3Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Applications using libpng before 1.6.55 may hang and read beyond allocated memory when processing certain valid PNG palettes through a specific quantization path. This can disrupt availability and may expose or corrupt limited data. Risk is highest where untrusted images are processed automatically.

Executive priority

Prioritize internet-facing and automated image-processing systems, then other affected workloads. The high availability impact supports prompt remediation, although exploitation requires specific application behavior and palette conditions. There is no source-backed evidence here of active exploitation.

Technical view

CVE-2026-25646 is an out-of-bounds heap read in png_set_quantize(). With no histogram and a palette exceeding twice the display-supported color maximum, certain valid palettes trigger an infinite loop reading beyond an internal allocation. The issue affects libpng versions before 1.6.55 and carries CVSS 4.0 score 8.3.

Likely exposure

Exposure requires libpng earlier than 1.6.55 and use of png_set_quantize() under the documented palette and histogram conditions. Image-processing services, converters, or embedded products accepting untrusted PNGs warrant review. The bundle does not identify every downstream application or distribution package affected.

Exploitation context

The CVSS vector describes network reachability without privileges or user interaction, but high complexity and prerequisite conditions. The source bundle marks this CVE as absent from KEV and provides no evidence of active exploitation. Valid PNG files can reach the vulnerable condition; no malformed PNG is required.

Researcher notes

The supplied title and CWE set reference heap buffer overflow classes, while the detailed advisory description specifically characterizes an infinite-looping out-of-bounds read. Impact should therefore be assessed from the documented behavior and CVSS impacts, not assumed to provide code execution. Downstream exposure depends on API usage and build linkage.

Mitigation direction

  • Upgrade upstream libpng to version 1.6.55 or later.
  • Apply the relevant vendor-provided backport where replacing the upstream library is unsuitable.
  • Inventory statically linked, bundled, and transitive libpng copies that package managers may miss.
  • Until patched, restrict untrusted PNG processing that reaches the affected quantization function.

Validation and detection

  • Confirm runtime and embedded libpng versions are 1.6.55 or vendor-fixed builds.
  • Trace whether applications call png_set_quantize() without supplying a histogram.
  • Review image-processing entry points for remotely supplied or otherwise untrusted PNG files.
  • Run approved regression and availability tests after updating the library or vendor package.
Prepared
Confidence
high
Sources
6

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

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-122: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-125: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-126: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-25646 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.3 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
3ADP providers
43Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.3CVSS 4.0HighCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N——GitHub_M
7CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H2.24.7redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

8.3High
CVSS 4.0 vector shape for CVE-2026-25646Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPlibpng: LIBPNG has a heap buffer overflow in png_set_quantize
other:Red Hat severity ratingcvssV3_1
  • 2026-02-10T18:01:28.232Z: Reported to Red Hat.
  • 2026-02-10T17:04:38.501Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
pnggrouplibpng< 1.6.55Listed
Weakness

CWE details

CWE-122CWE-125CWE-126

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-122 · source CWE mapping

Heap-based Buffer Overflow

Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-125 · source CWE mapping

Out-of-bounds Read

Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-126 · source CWE mapping

Buffer Over-read

Buffer Over-read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs