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CVE Record

CVE-2026-42216: OpenEXR: Out-of-bounds read in `IDManifest::init()` during prefix expansion

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From versions 3.0.0 to before 3.2.9, 3.3.0 to before 3.3.11, and 3.4.0 to before 3.4.11, IDManifest::init() reconstructs strings from a prefix-compressed representation. If the previous string is longer than 255 bytes, the next string is expected to begin with a 2-byte prefix length. The code reads stringList[i][0] and stringList[i][1] without checking that the current string has at least two bytes. This issue has been patched in versions 3.2.9, 3.3.11, and 3.4.11.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A malformed EXR image can cause vulnerable OpenEXR software to read beyond expected memory boundaries while rebuilding embedded identifier strings. Systems that automatically accept or process untrusted EXR files face the greatest concern. The reported consequences include serious data-confidentiality and availability impact, although the supplied sources do not confirm real-world exploitation.

Executive priority

Prioritize internet-facing upload, rendering, media, and asset-processing systems, then internal pipelines handling externally supplied files. Patch promptly because severity is high and exploitation conditions are favorable in the reported vector. Emergency incident response is not justified solely by this bundle because active exploitation is unconfirmed.

Technical view

OpenEXR IDManifest::init() mishandles a prefix-compressed string following a previous string longer than 255 bytes. It reads the current entry’s first two bytes without confirming they exist, causing an out-of-bounds read. CVE-2026-42216 affects 3.0.0–3.2.8, 3.3.0–3.3.10, and 3.4.0–3.4.10. CVSS 4.0 is 8.8.

Likely exposure

Likely exposure exists wherever affected OpenEXR libraries parse EXR content, directly or through dependent imaging, rendering, media, or asset-processing software. Risk is highest for internet-facing upload services and unattended processing pipelines accepting untrusted images. The bundle provides no product-specific deployment inventory, so organizations must identify embedded and transitive OpenEXR copies.

Exploitation context

The supplied CVSS vector describes network-reachable, low-complexity exploitation requiring neither privileges nor user interaction, with high confidentiality and availability impacts. However, practical reachability depends on how an application receives and parses EXR files. The source bundle marks KEV false and provides no evidence of active exploitation or a public exploit.

Researcher notes

The defect is CWE-125 and CWE-130: insufficient validation of a variable-length prefix representation permits a two-byte read from an undersized current string. Analysis should focus on whether attacker-controlled EXR metadata reaches IDManifest parsing. The bundle does not establish exploit reliability, exposed data scope, crash behavior, or affected downstream applications.

Mitigation direction

  • Upgrade OpenEXR 3.2.x to 3.2.9 or later.
  • Upgrade OpenEXR 3.3.x to 3.3.11 or later.
  • Upgrade OpenEXR 3.4.x to 3.4.11 or later.
  • Apply applicable vendor or distribution security updates, including relevant Red Hat errata.
  • Until updated, restrict untrusted EXR ingestion and isolate automated image-processing services.

Validation and detection

  • Inventory direct, transitive, bundled, and system OpenEXR library versions.
  • Confirm no installed version falls within any affected range.
  • Verify running services load the updated library, not an older bundled copy.
  • Test that EXR-processing workflows still operate after updating.
  • Review upload endpoints and automated pipelines for untrusted EXR processing.
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

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-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-130: 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-2026-42216 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
8.8 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/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
2ADP providers
11Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical 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
8.8CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N——GitHub_M
8.1CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H2.85.2redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

8.8High
CVSS 4.0 vector shape for CVE-2026-42216Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPOpenEXR: OpenEXR: Information disclosure and denial of service via malformed EXR files
other:Red Hat severity ratingcvssV3_1
  • 2026-05-07T05:02:12.164Z: Reported to Red Hat.
  • 2026-05-07T04:01:59.602Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AcademySoftwareFoundationopenexr>= 3.0.0, < 3.2.9, >= 3.3.0, < 3.3.11, >= 3.4.0, < 3.4.11Listed
Weakness

CWE details

CWE-125CWE-130

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

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-130 · source CWE mapping

Improper Handling of Length Parameter Inconsistency

Improper Handling of Length Parameter Inconsistency represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs