# CVE-2026-34588: OpenEXR has a signed 32-bit Overflow in PIZ Decoder Leads to OOB Read/Write > A signed integer overflow in the PIZ decoder allows attackers to trigger out-of-bounds reads and writes via crafted EXR files, potentially leading to code execution. - **Severity:** High 8.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 6 Apr 2026 - **Updated:** 9 Sep 2026 - **Also known as:** ALSA-2026:15887, ALSA-2026:15888, ALSA-2026:19146, ALSA-2026:19359, BELL-CVE-2026-34588, CLSA-2026-1776950014, CLSA-2026-1776950756, DEBIAN-CVE-2026-34588, ECHO-1364-3d73-650f, GHSA-588r-cr5c-w6hf, JLSEC-2026-148, PYSEC-2026-2845, RHSA-2026:15887, RHSA-2026:15888, RHSA-2026:17656, RHSA-2026:17658, RHSA-2026:17659, RHSA-2026:17660, RHSA-2026:19146, RHSA-2026:19359, RHSA-2026:19587, RLSA-2026:15887, RLSA-2026:15888, RLSA-2026:19146, RLSA-2026:19359, ROOT-OS-DEBIAN-11-CVE-2026-34588, ROOT-OS-DEBIAN-12-CVE-2026-34588, ROOT-OS-DEBIAN-13-CVE-2026-34588, UBUNTU-CVE-2026-34588 ## What is CVE-2026-34588? CVE-2026-34588 is a high-severity vulnerability in Openexr Openexr, published on 6 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.1.0 to before 3.2.7, 3.3.9, and 3.4.9, internal_exr_undo_piz() advances the working wavelet pointer with signed 32-bit arithmetic. Because nx, ny, and wcount are int, a crafted EXR file can make this product overflow and wrap. The next channel then decodes from an incorrect address. The wavelet decode path operates in place, so this yields both out-of-bounds reads and out-of-bounds writes. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9. Weakness: CWE-787 (Out-of-bounds Write), CWE-190 (Integer Overflow or Wraparound), CWE-125 (Out-of-bounds Read) ## Which versions are affected by CVE-2026-34588? 7 open source packages ship an affected version, including openexr and OpenEXR. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `openexr` | PyPI | From 3.1.0 | 3.2.7, 3.3.9, 3.4.9 | | `openexr` | PyPI | From 3.1.0 | 3.2.7 | | `openexr` | PyPI | From 3.3.0 | 3.3.9 | | `openexr` | PyPI | From 3.4.0 | 3.4.9 | | `OpenEXR` | PyPI | From 3.1.0 | 3.2.7 | | `OpenEXR` | PyPI | From 3.3.0 | 3.3.9 | | `OpenEXR` | PyPI | From 3.4.0 | 3.4.9 | | `openexr` | AlmaLinux:10 | All versions | 3.1.10-8.el10_1.2 | | `openexr` | AlmaLinux:10 | All versions | 3.1.10-8.el10_2.2 | | `openexr-devel` | AlmaLinux:10 | All versions | 3.1.10-8.el10_1.2 | | `openexr-devel` | AlmaLinux:10 | All versions | 3.1.10-8.el10_2.2 | | `openexr-libs` | AlmaLinux:10 | All versions | 3.1.10-8.el10_1.2 | | `openexr-libs` | AlmaLinux:10 | All versions | 3.1.10-8.el10_2.2 | | `openexr` | AlmaLinux:9 | All versions | 3.1.1-3.el9_7.2 | | `openexr` | AlmaLinux:9 | All versions | 3.1.1-3.el9_8.2 | | `openexr-devel` | AlmaLinux:9 | All versions | 3.1.1-3.el9_7.2 | | `openexr-devel` | AlmaLinux:9 | All versions | 3.1.1-3.el9_8.2 | | `openexr-libs` | AlmaLinux:9 | All versions | 3.1.1-3.el9_7.2 | | `openexr-libs` | AlmaLinux:9 | All versions | 3.1.1-3.el9_8.2 | | `openexr` | Red Hat:enterprise_linux:10.1 | All versions | 0:3.1.10-8.el10_1.2 | | `openexr-debuginfo` | Red Hat:enterprise_linux:10.1 | All versions | 0:3.1.10-8.el10_1.2 | | `openexr-debugsource` | Red Hat:enterprise_linux:10.1 | All versions | 0:3.1.10-8.el10_1.2 | | `openexr-devel` | Red Hat:enterprise_linux:10.1 | All versions | 0:3.1.10-8.el10_1.2 | | `openexr-libs` | Red Hat:enterprise_linux:10.1 | All versions | 0:3.1.10-8.el10_1.2 | | `openexr-libs-debuginfo` | Red Hat:enterprise_linux:10.1 | All versions | 0:3.1.10-8.el10_1.2 | | `openexr` | Red Hat:enterprise_linux:10.2 | All versions | 0:3.1.10-8.el10_2.2 | | `openexr-debuginfo` | Red Hat:enterprise_linux:10.2 | All versions | 0:3.1.10-8.el10_2.2 | | `openexr-debugsource` | Red Hat:enterprise_linux:10.2 | All versions | 0:3.1.10-8.el10_2.2 | | `openexr-devel` | Red Hat:enterprise_linux:10.2 | All versions | 0:3.1.10-8.el10_2.2 | | `openexr-libs` | Red Hat:enterprise_linux:10.2 | All versions | 0:3.1.10-8.el10_2.2 | | `openexr-libs-debuginfo` | Red Hat:enterprise_linux:10.2 | All versions | 0:3.1.10-8.el10_2.2 | | `openexr` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_7.2 | | `openexr` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_8.2 | | `openexr-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_7.2 | | `openexr-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_8.2 | | `openexr-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_7.2 | | `openexr-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_8.2 | | `openexr-libs` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_7.2 | | `openexr-libs` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_8.2 | | `openexr-libs-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:3.1.1-3.el9_7.2 | Products: Openexr Openexr. ## How do I fix CVE-2026-34588? Upgrade openexr to a fixed version for your release line: 3.2.7, 3.3.9 or 3.4.9. ## Is CVE-2026-34588 being exploited? There is no known exploitation of CVE-2026-34588 in the wild and no public exploit code. ## Other vulnerabilities in Openexr Openexr - [CVE-2023-5841](https://insights.sbomify.com/CVE-2023-5841/): OpenEXR Heap Overflow in Scanline Deep Data Parsing (critical 9.1) - [CVE-2026-41142](https://insights.sbomify.com/CVE-2026-41142/): OpenEXR is Vulnerable to Integer overflow in ImageChannel::resize leads to heap OOB write via OpenEXRUtil public API (high 8.8) - [CVE-2026-42216](https://insights.sbomify.com/CVE-2026-42216/): OpenEXR: Out-of-bounds read in `IDManifest::init()` during prefix expansion (high 8.8) - [CVE-2017-9111](https://insights.sbomify.com/CVE-2017-9111/): OpenEXR invalid write (high 8.8) - [CVE-2017-9113](https://insights.sbomify.com/CVE-2017-9113/): Memory corruption in n/a (high 8.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-34588 and fix it if it is affected. What it is: CVE-2026-34588 is a high-severity vulnerability in Openexr Openexr, published on 6 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-34588 in the wild and no public exploit code. Affected packages and fixed versions: - openexr (PyPI): affected from 3.1.0; fixed in 3.2.7, 3.3.9, 3.4.9 - openexr (PyPI): affected from 3.1.0; fixed in 3.2.7 - openexr (PyPI): affected from 3.3.0; fixed in 3.3.9 - openexr (PyPI): affected from 3.4.0; fixed in 3.4.9 - OpenEXR (PyPI): affected from 3.1.0; fixed in 3.2.7 - OpenEXR (PyPI): affected from 3.3.0; fixed in 3.3.9 - OpenEXR (PyPI): affected from 3.4.0; fixed in 3.4.9 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-34588/ (Markdown: https://insights.sbomify.com/CVE-2026-34588/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34588 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34588 - OSV: https://osv.dev/vulnerability/CVE-2026-34588 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-34588/ Summaries are generated and may contain mistakes; the official description above is the record.