CVE-2026-63209

HIGHPre-NVD 7.57.5
EchelonGraph scoreHIGH confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-10-20. A secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this week

Also known asEUVD-2026-88977 (ENISA EUVD) · GHSA-259r-337f-4rfw (GitHub Security Advisories) · GO-2026-5841 (OSV.dev)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

compress provides various compression algorithms. Prior to version 1.18.7, 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. This issue has been patched in version 1.18.7.

CVSS v3
7.5
EG Score
7.5HIGHhigh confidence
EG Risk
49
EG Risk 49/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
47th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 29, 2026

Last Modified

September 30, 2026

Advisory Details (3)

Auto-updated Sep 29, 2026
Patch available. Sources: github_commit, github_release, github.
GitHub advisoryMentions a patch (unverified)

Integer Overflow or Wraparound and Out-of-bounds Write in compress · Advisory · klauspost/compress · GitHub

https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw
GitHub release Patch Available

v1.18.7

Patch available: klauspost/compress v1.18.7

https://github.com/klauspost/compress/releases/tag/v1.18.7
GitHub commit

commit 539243b8823e (klauspost/compress)

Fix landed in klauspost/compress commit 539243b8823e — awaiting tagged release

https://github.com/klauspost/compress/commit/539243b8823ee8f03e49969823d57c348c917536

Patch Availability(29)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9:17918295302026-10-19redhat
redhatrhacm2/lighthouse-coredns-rhel9:17906702312026-10-19redhat
redhatopenshift-logging/logging-loki-rhel9:17915007292026-10-14redhat
redhatrhosdt/tempo-jaeger-query-rhel9:17914525692026-10-08redhat
redhatgrafana13-1-main-13.1.6-0.4.hum12026-09-28redhat
redhatloki3-6-main-3.6.17-0.3.hum12026-09-28redhat
redhatgrafana13-2-main-13.2.1-0.8.hum12026-09-28redhat
redhattempo3-0-main-3.0.3-0.4.hum12026-09-28redhat
redhatgrafana12-4-main-12.4.10-0.9.hum12026-09-28redhat
redhatspire1-15-main-1.15.3-0.2.hum12026-09-28redhat
redhattempo2-10-main-2.10.8-0.4.hum12026-09-28redhat
redhatloki3-7-main-3.7.8-0.3.hum12026-09-28redhat
redhattrivy-main-0.74.0-0.4.hum12026-09-28redhat
redhatbuildah-main-1.45.1-1.hum12026-09-23redhat
redhatpodman-main-6.1.2-1.hum12026-09-23redhat
redhatskopeo-main-1.24.1-1.hum12026-09-23redhat
redhatk6v2-main-2.3.0-0.1.hum12026-09-22redhat
redhatgrype-main-0.119.0-0.1.hum12026-09-18redhat
redhatsyft-main-1.52.0-0.1.hum12026-09-18redhat
redhathelm3-main-3.22.0-0.2.hum12026-09-17redhat
redhathelm4-main-4.3.0-0.2.hum12026-09-17redhat
redhatopentelemetry-collector-k8s-main-0.161.0-0.1.hum12026-09-17redhat
redhatopentelemetry-collector-main-0.161.0-0.1.hum12026-09-16redhat
redhatopentelemetry-collector-contrib-main-0.161.0-0.1.hum12026-09-16redhat
redhatnats-server2-14-main-2.14.7-0.1.hum12026-09-16redhat
redhatrekor-main-1.5.4-0.1.hum12026-08-22redhat
redhatk6v1-main-1.8.1-0.1.hum12026-08-12redhat
redhatnats-server2-12-main-2.12.15-0.1.hum12026-08-12redhat
gogithub.com/klauspost/compress @ 1.18.7 (fixes <= 1.18.6)—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
golang-github-klauspost-compress1.18.0+ds1-1 ... 1.20.0+ds1-1 (7 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
golang-github-klauspost-compress1.18.0+ds1-1, 1.18.1+ds1-1, 1.18.6+ds1-1, 1.18.6+ds1-2
  • every version up to 1.19.0+ds1-1: fixed in 1.19.0+ds1-1
—
Go(1)
PackageVulnerable rangeFix by version rangeDependents
github.com/klauspost/compress—
  • 1.16.0 up to 1.18.7: fixed in 1.18.7
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(18)

Data Freshness Timeline

(refreshed 11× in last 7d / 70× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-11-01 07:41 UTCGHSA enrichmentGHSA-259r-337f-4rfw · GitHub severity HIGH · GitHub CVSS 7.5
  3. 2026-11-01 07:41 UTCEG score recompute
  4. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  5. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  6. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-10-28 22:33 UTCEG score recompute
  8. 2026-10-28 21:25 UTCOSV refresh
  9. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  13. 2026-10-25 14:13 UTCEG score recompute
  14. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  15. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  16. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  17. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  18. 2026-10-21 01:43 UTCEG score recompute
  19. 2026-10-21 01:43 UTCVendor advisory
  20. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  21. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  22. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  23. 2026-10-18 03:23 UTCEG score recompute
  24. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  25. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.4% · 28th percentile
Show 57 more
  1. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  2. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  3. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  4. 2026-10-13 12:03 UTCEG score recompute
  5. 2026-10-13 12:03 UTCVendor advisory
  6. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  7. 2026-10-12 15:49 UTCEG score recompute
  8. 2026-10-11 19:33 UTCVendor advisory
  9. 2026-10-11 19:33 UTCEG score recompute
  10. 2026-10-11 16:48 UTCEG score recompute
  11. 2026-10-11 14:10 UTCEG score recompute
  12. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  13. 2026-10-11 07:36 UTCEG score recompute
  14. 2026-10-11 07:36 UTCVendor advisory
  15. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  16. 2026-10-10 19:39 UTCVendor advisory
  17. 2026-10-10 07:42 UTCEG score recompute
  18. 2026-10-10 07:42 UTCVendor advisory
  19. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  20. 2026-10-09 19:45 UTCVendor advisory
  21. 2026-10-09 07:48 UTCVendor advisory
  22. 2026-10-08 19:50 UTCEG score recompute
  23. 2026-10-08 19:50 UTCVendor advisory
  24. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  25. 2026-10-08 07:28 UTCEG score recompute
  26. 2026-10-08 07:28 UTCVendor advisory
  27. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  28. 2026-10-07 19:31 UTCVendor advisory
  29. 2026-10-07 07:25 UTCVendor advisory
  30. 2026-10-06 19:28 UTCEG score recompute
  31. 2026-10-06 19:28 UTCVendor advisory
  32. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  33. 2026-10-06 07:31 UTCVendor advisory
  34. 2026-10-05 19:34 UTCEG score recompute
  35. 2026-10-05 19:34 UTCVendor advisory
  36. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  37. 2026-10-05 07:38 UTCEG score recompute
  38. 2026-10-05 07:38 UTCVendor advisory
  39. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  40. 2026-10-04 19:41 UTCVendor advisory
  41. 2026-10-04 07:44 UTCVendor advisory
  42. 2026-10-03 19:47 UTCEG score recompute
  43. 2026-10-03 19:47 UTCVendor advisory
  44. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  45. 2026-10-03 07:50 UTCVendor advisory
  46. 2026-10-02 19:50 UTCEG score recompute
  47. 2026-10-02 19:50 UTCVendor advisory
  48. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  49. 2026-10-01 19:55 UTCEG score recompute
  50. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  51. 2026-09-30 17:29 UTCEG score recompute
  52. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  53. 2026-09-29 17:32 UTCEG score recompute
  54. 2026-09-29 16:45 UTCEG score recompute
  55. 2026-09-29 15:23 UTCEG score recompute
  56. 2026-09-29 15:09 UTCEG score recomputeFirst assessed: 7.5 HIGH
  57. 2026-09-29 15:08 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-63209?
CVE-2026-63209 is a high-severity vulnerability; its CVE record was published on September 29, 2026. compress provides various compression algorithms. Prior to version 1.18.7, 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…
When was the CVE record for CVE-2026-63209 published?
The CVE record for CVE-2026-63209 was published on September 29, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 30, 2026; the record at its source may have been updated since.
Is CVE-2026-63209 actively exploited?
CVE-2026-63209 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (47th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-63209?
CVE-2026-63209 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-63209?
A fix for CVE-2026-63209 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-63209 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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