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NVD / CVE Program· CNA GitHub_M

CVE-2026-34378: OpenEXR has a signed integer overflow in generic_unpack() when parsing EXR files with crafted negative dataWindow.min.x

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.27% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: AcademySoftwareFoundation openexr 3.4.9.

Low priority for now. Upgrade to AcademySoftwareFoundation openexr 3.4.9 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.4.0 to before 3.4.9, a missing bounds check on the dataWindow attribute in EXR file headers allows an attacker to trigger a signed integer overflow in generic_unpack(). By setting dataWindow.min.x to a large negative value, OpenEXRCore computes an enormous image width, which is later used in a signed integer multiplication that overflows, causing the process to terminate with SIGILL via UBSan. This vulnerability is fixed in 3.4.9.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Apr 6, 2026
Updated
Oct 26, 2026
EPSS
0.2% · 19th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
6.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
openexropenexr

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • openexr openexr3.4.0 and later · before 3.4.9

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • AcademySoftwareFoundation openexr

    • >= 3.4.0, < 3.4.9affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.22openexrfrom 3.4.0 · before 3.3.11-r03.3.11-r0
Alpine:v3.23openexrfrom 3.4.0 · before 3.4.13-r03.4.13-r0
Alpine:v3.24openexrfrom 3.4.0 · before 3.4.10-r03.4.10-r0
Debian:14openexrbefore 3.4.14-0.13.4.14-0.1
openSUSE:Tumbleweedopenexrbefore 3.4.9-1.13.4.9-1.1

Same product

openexr: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-5841OpenEXR Heap Overflow in Scanline Deep Data Parsing
    36Monitor
  • CVE-2021-23169A heap-buffer overflow was found in the copyIntoFrameBuffer function of OpenEXR in versions before 3.0.1.
    36Monitor
  • CVE-2017-9115In OpenEXR 2.2.0, an invalid write of size 2 in the = operator function in half.h could cause the application to crash or execute arbitrary
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-34544Apr 1, 2026 · OpenEXR: integer overflow to OOB write in uncompress_b44_impl()
    33Monitor
  • ← EarlierCVE-2026-34545Apr 1, 2026 · OpenEXR: integer overflow lead to OOB in HTJ2K decoder
    33Monitor
  • Later →CVE-2026-34379Apr 6, 2026 · OpenEXR has a misaligned write in LossyDctDecoder_execute leading to undefined behavior (DWA/DWAB decompression)
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
AcademySoftwareFoundation openexr3.4.9 · descriptionVendor (CNA)
alpine:openexr3.3.11-r0 · Alpine:v3.22Package registry (OSV)
debian:openexr3.4.14-0.1 · Debian:14Package registry (OSV)
opensuse:openexr3.4.9-1.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-4114231 days apartOpenEXR is Vulnerable to Integer overflow in ImageChannel::resize leads to heap OOB write via OpenEXRUtil public API
    35Monitor
  • CVE-2026-345890 days apartOpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write
    33Monitor
  • CVE-2026-345445 days apartOpenEXR: integer overflow to OOB write in uncompress_b44_impl()
    33Monitor
  • CVE-2026-4024415 days apartOpenEXR has integer overflow in DWA setupChannelData planarUncRle pointer arithmetic (missed variant of CVE-2026-34589)
    33Monitor
  • CVE-2026-4025015 days apartOpenEXR has integer overflow in DWA decoder outBufferEnd pointer arithmetic (missed variant of CVE-2026-34589)
    33Monitor
  • CVE-2026-4466373 days apartOpenEXR: Integer overflow in the HTJ2K decoder leads to heap-buffer-overflow
    28Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-190 · Integer Overflow or Wraparound

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records