# CVE-2026-15534: Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. > An attacker can trigger out-of-bounds heap reads and writes in the Perl regex engine via integer overflow, potentially causing crashes or arbitrary code execution. - **Severity:** Medium 5.7 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H`) - **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:** 9 Aug 2026 - **Updated:** 8 Sep 2026 - **Also known as:** AZL-94670, DEBIAN-CVE-2026-15534, ECHO-8d4e-0265-d9a8, GHSA-2cxw-qmfc-3vx3, MINI-692f-2gqh-cqch, MINI-6fmf-8f4j-q3h5, MINI-8vj8-xjvm-q3gf, MINI-c2v2-v48m-gv52, MINI-q7mm-533p-7p9x, OESA-2026-3425, RHSA-2026:63403, UBUNTU-CVE-2026-15534 ## What is CVE-2026-15534? CVE-2026-15534 is a medium-severity memory corruption vulnerability in perl, published on 9 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory. 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-2026-15534? | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `perl` | Red Hat:hummingbird:1 | All versions | 0:5.42.2-525.1.hum1 | | `perl-Attribute-Handlers` | Red Hat:hummingbird:1 | All versions | 0:1.03-525.1.hum1 | | `perl-AutoLoader` | Red Hat:hummingbird:1 | All versions | 0:5.74-525.1.hum1 | | `perl-AutoSplit` | Red Hat:hummingbird:1 | All versions | 0:5.74-525.1.hum1 | | `perl-B` | Red Hat:hummingbird:1 | All versions | 0:1.89-525.1.hum1 | | `perl-Benchmark` | Red Hat:hummingbird:1 | All versions | 0:1.27-525.1.hum1 | | `perl-Class-Struct` | Red Hat:hummingbird:1 | All versions | 0:0.68-525.1.hum1 | | `perl-Config-Extensions` | Red Hat:hummingbird:1 | All versions | 0:0.03-525.1.hum1 | | `perl-DBM_Filter` | Red Hat:hummingbird:1 | All versions | 0:0.07-525.1.hum1 | | `perl-Devel-Peek` | Red Hat:hummingbird:1 | All versions | 0:1.36-525.1.hum1 | | `perl-Devel-SelfStubber` | Red Hat:hummingbird:1 | All versions | 0:1.06-525.1.hum1 | | `perl-DirHandle` | Red Hat:hummingbird:1 | All versions | 0:1.05-525.1.hum1 | | `perl-Dumpvalue` | Red Hat:hummingbird:1 | All versions | 0:2.27-525.1.hum1 | | `perl-DynaLoader` | Red Hat:hummingbird:1 | All versions | 0:1.57-525.1.hum1 | | `perl-English` | Red Hat:hummingbird:1 | All versions | 0:1.11-525.1.hum1 | | `perl-Errno` | Red Hat:hummingbird:1 | All versions | 0:1.38-525.1.hum1 | | `perl-ExtUtils-Constant` | Red Hat:hummingbird:1 | All versions | 0:0.25-525.1.hum1 | | `perl-ExtUtils-Embed` | Red Hat:hummingbird:1 | All versions | 0:1.35-525.1.hum1 | | `perl-ExtUtils-Miniperl` | Red Hat:hummingbird:1 | All versions | 0:1.14-525.1.hum1 | | `perl-Fcntl` | Red Hat:hummingbird:1 | All versions | 0:1.20-525.1.hum1 | | `perl-File-Basename` | Red Hat:hummingbird:1 | All versions | 0:2.86-525.1.hum1 | | `perl-File-Compare` | Red Hat:hummingbird:1 | All versions | 0:1.100.800-525.1.hum1 | | `perl-File-Copy` | Red Hat:hummingbird:1 | All versions | 0:2.41-525.1.hum1 | | `perl-File-DosGlob` | Red Hat:hummingbird:1 | All versions | 0:1.12-525.1.hum1 | | `perl-File-Find` | Red Hat:hummingbird:1 | All versions | 0:1.44-525.1.hum1 | | `perl-File-stat` | Red Hat:hummingbird:1 | All versions | 0:1.14-525.1.hum1 | | `perl-FileCache` | Red Hat:hummingbird:1 | All versions | 0:1.10-525.1.hum1 | | `perl-FileHandle` | Red Hat:hummingbird:1 | All versions | 0:2.05-525.1.hum1 | | `perl-FindBin` | Red Hat:hummingbird:1 | All versions | 0:1.54-525.1.hum1 | | `perl-GDBM_File` | Red Hat:hummingbird:1 | All versions | 0:1.24-525.1.hum1 | | `perl-Getopt-Std` | Red Hat:hummingbird:1 | All versions | 0:1.14-525.1.hum1 | | `perl-Hash-Util` | Red Hat:hummingbird:1 | All versions | 0:0.32-525.1.hum1 | | `perl-Hash-Util-FieldHash` | Red Hat:hummingbird:1 | All versions | 0:1.27-525.1.hum1 | | `perl-I18N-Collate` | Red Hat:hummingbird:1 | All versions | 0:1.02-525.1.hum1 | | `perl-I18N-LangTags` | Red Hat:hummingbird:1 | All versions | 0:0.45-525.1.hum1 | | `perl-I18N-Langinfo` | Red Hat:hummingbird:1 | All versions | 0:0.24-525.1.hum1 | | `perl-IO` | Red Hat:hummingbird:1 | All versions | 0:1.55-525.1.hum1 | | `perl-IPC-Open3` | Red Hat:hummingbird:1 | All versions | 0:1.24-525.1.hum1 | | `perl-Locale-Maketext-Simple` | Red Hat:hummingbird:1 | All versions | 0:0.21-525.1.hum1 | | `perl-Math-Complex` | Red Hat:hummingbird:1 | All versions | 0:1.63-525.1.hum1 | ## How do I fix CVE-2026-15534? Apply the vendor's patch. ## Is CVE-2026-15534 being exploited? There is no known exploitation of CVE-2026-15534 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-15534 and fix it if it is affected. What it is: CVE-2026-15534 is a medium-severity memory corruption vulnerability in perl, published on 9 Aug 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-2026-15534 in the wild and no public exploit code. Affected product: perl. No package-level version data is available, so check the vendor advisory linked from the reference page. 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-2026-15534/ (Markdown: https://insights.sbomify.com/CVE-2026-15534/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15534 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15534 - OSV: https://osv.dev/vulnerability/CVE-2026-15534 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-15534/ Summaries are generated and may contain mistakes; the official description above is the record.