CVE-2026-48702: Github.com/sigstore/rekor Rekor Has An OOM Condition Vulnerability

HIGH
Advisory Identifier: GHSA-47q9-m4ww-924m
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CVSS 7.5
CWE-770
Published
Advisory Summary

CVE-2026-48702 is a HIGH (CVSS 7.5) rekor has an oom condition vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Github.com/sigstore/rekor libraries in the Go ecosystem. The issue involves rekor has an oom condition due to unbounded gzip decompression in alpine apk parsing logic. Remediation is available by upgrading affected packages to version 1.5.2.

CVE-2026-48702 at a Glance

CVE Identifier CVE-2026-48702
GHSA Identifier GHSA-47q9-m4ww-924m
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Github.com/sigstore/rekor
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-48702

To remediate this vulnerability, upgrade all affected Github.com/sigstore/rekor dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/sigstore/rekor fixed: 1.5.2 
Upgrade github.com/sigstore/rekor to 1.5.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/sigstore/rekor

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-48702, inspect your project dependencies for Github.com/sigstore/rekor:

inspect dependencies for github.com/sigstore/rekor

Analyze the terminal output to locate any version of Github.com/sigstore/rekor in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.5.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Github.com/sigstore/rekor, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Description The `Package.Unmarshal()` function in `pkg/types/alpine/apk.go` decompresses the signature and control gzip members of an APK file into in-memory buffers without bounding the total decompressed size. The existing `max_apk_metadata_size` check (default 1MB) is only applied to individual tar entry header sizes after decompression completes, so it does not prevent a decompression bomb from consuming unbounded heap memory. An attacker can craft a gzip stream that compresses at a ~1000:1 ratio (e.g., 2MB compressed zeros → 2GB decompressed). When submitted as spec.package.content in an Alpine `ProposedEntry`, the server decompresses the full payload into memory during request processing, triggering a fatal Go runtime out-of-memory error or OS OOM-kill that cannot be caught by the server's recover() middleware. This is reachable via two unauthenticated endpoints: - POST /api/v1/log/entries (createLogEntry) - POST /api/v1/log/entries/retrieve (searchLogQuery) Both invoke `V001Entry.Canonicalize()` → `fetchExternalEntities()` → `apk.Unmarshal(packageData)`, which performs the unbounded decompression. ## Workarounds There is no effective workaround. Setting `max_request_body_size` reduces but does not eliminate exposure due to the ~1000:1 compression ratio (a 1MB body limit still allows ~1GB heap allocation). Setting `max_apk_metadata_size` has no effect on this vulnerability since the check is applied after decompression.

CVE-2026-48702 Affected Github.com/sigstore/rekor Versions

1 component(s)
Fixed Versions:
1.5.2
Product / Package Ecosystem Affected Versions Fixed Version
github.com/sigstore/rekor
golang/github.com/sigstore/rekor
Go
≥ 0.3.0
< 1.5.2
1.5.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/sigstore/rekor/security/advisories/GHSA-47q9-m4ww-924m
Github.com/sigstore/rekor Source Repository REPOSITORY
https://github.com/sigstore/rekor

Frequently Asked Questions

What is CVE-2026-48702?
CVE-2026-48702 is a security vulnerability in Github.com/sigstore/rekor involving Rekor has an OOM Condition due to Unbounded gzip Decompression in Alpine APK Parsing Logic under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Github.com/sigstore/rekor versions are affected?
Affected versions include releases prior to 1.5.2 across affected packages: github.com/sigstore/rekor.
What version fixes CVE-2026-48702?
Upgrading to 1.5.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/sigstore/rekor affected?
Yes, github.com/sigstore/rekor is affected in releases prior to 1.5.2. Upgrade your dependency to 1.5.2 or later.
What is the CVSS score of CVE-2026-48702?
CVE-2026-48702 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-48702?
CVE-2026-48702 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check Go dependencies for CVE-2026-48702?
Run the dependency tree command: 'inspect dependencies for github.com/sigstore/rekor'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-47q9-m4ww-924m",
  "modified" : "2026-06-25T21:33:36Z",
  "published" : "2026-06-25T21:33:36Z",
  "aliases" : [ "CVE-2026-48702" ],
  "summary" : "Rekor has an OOM Condition due to Unbounded gzip Decompression in Alpine APK Parsing Logic",
  "details" : "## Description\n\nThe `Package.Unmarshal()` function in `pkg/types/alpine/apk.go` decompresses the signature and control gzip members of an APK file into in-memory buffers without bounding the total decompressed size. The existing `max_apk_metadata_size` check (default 1MB) is only applied to individual tar entry header sizes after decompression completes, so it does not prevent a decompression bomb from consuming unbounded heap memory.\n\nAn attacker can craft a gzip stream that compresses at a ~1000:1 ratio (e.g., 2MB compressed zeros → 2GB decompressed). When submitted as spec.package.content in an Alpine `ProposedEntry`, the server decompresses the full payload into memory during request processing, triggering a fatal Go runtime out-of-memory error or OS OOM-kill that cannot be caught by the server's recover() middleware.\n\nThis is reachable via two unauthenticated endpoints:\n- POST /api/v1/log/entries (createLogEntry)\n- POST /api/v1/log/entries/retrieve (searchLogQuery)\n\nBoth invoke `V001Entry.Canonicalize()` → `fetchExternalEntities()` → `apk.Unmarshal(packageData)`, which performs the unbounded decompression.\n\n## Workarounds\n\nThere is no effective workaround. Setting `max_request_body_size` reduces but does not eliminate exposure due to the ~1000:1 compression ratio (a 1MB body limit still allows ~1GB heap allocation). Setting `max_apk_metadata_size` has no effect on this vulnerability since the check is applied after decompression.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/sigstore/rekor"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.3.0"
      }, {
        "fixed" : "1.5.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/sigstore/rekor/security/advisories/GHSA-47q9-m4ww-924m"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/sigstore/rekor"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-25T21:33:36Z",
    "nvd_published_at" : null
  }
}