CVE-2026-4176

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-03-29. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week
9.8EG
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: 0.8%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Fixed versions, as the CVE record's CNA (CPAN Security Group) states them: "Update to Perl stable release 5.40.4 or 5.42.2 or later, which include Compress::Raw::Zlib 2.222."

Perl versions from 5.9.4 before 5.40.4-RC1, from 5.41.0 before 5.42.2-RC1, from 5.43.0 before 5.43.9 contain a vulnerable version of Compress::Raw::Zlib.

Compress::Raw::Zlib is included in the Perl package as a dual-life core module, and is vulnerable to CVE-2026-3381 due to a vendored version of zlib which has several vulnerabilities, including CVE-2026-27171. The bundled Compress::Raw::Zlib was updated to version 2.221 in Perl blead commit c75ae9cc164205e1b6d6dbd57bd2c65c8593fe94.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
59
EG Risk 59/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.8% × 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 total (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
0.8%
EPSS %ILE
56th
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-19). 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: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: 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 total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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

March 29, 2026

Last Modified

June 17, 2026

Advisory Details (7)

Auto-updated Oct 13, 2026
Patch available. Sources: github_commit.
Web page

oss-security - Re: CVE-2026-4176: Perl versions from 5.9.4 before 5.40.4-RC1, from 5.41.0 before 5.42.2-RC1, from 5.43.0 before 5.43.9 contain a vulnerable version of Compress::Raw::Zlib

http://www.openwall.com/lists/oss-security/2026/03/30/2
Web page

perldelta - what is new for perl v5.42.2 - metacpan.org

https://metacpan.org/release/SHAY/perl-5.42.2/changes
Web page

perldelta - what is new for perl v5.40.4 - metacpan.org

https://metacpan.org/release/SHAY/perl-5.40.4/changes
Web page

CVE-2026-3381: Compress::Raw::Zlib versions through 2.219 for Perl use potentially insecure versions of zlib | Simplelists

https://lists.security.metacpan.org/cve-announce/msg/37638919/
GitHub commit

commit c75ae9cc1642 (Perl/perl5)

Fix landed in Perl/perl5 commit c75ae9cc1642 — awaiting tagged release

https://github.com/Perl/perl5/commit/c75ae9cc164205e1b6d6dbd57bd2c65c8593fe94

Vendor Advisories for CVE-2026-4176(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(5 across 5 ecosystems)
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
perl—
  • 5.9.4 up to 5.42.2-r0: fixed in 5.42.2-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
perl—
  • every version up to 5.10.0-21: fixed in 5.10.0-21
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
perl—
  • every version up to 5.10.0-21: fixed in 5.10.0-21
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
perl—
  • every version up to 5.10.0-21: fixed in 5.10.0-21
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
perl—
  • every version up to 5.10.0-21: fixed in 5.10.0-21
—

Data Freshness Timeline

(refreshed 20× in last 7d / 46× 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.

Showing the most recent 100 of 248 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 148 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-20 05:32 UTCEG score recompute
  2. 2026-10-20 05:31 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  4. 2026-10-19 07:03 UTCEG score recompute
  5. 2026-10-19 07:03 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  6. 2026-10-18 09:20 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  7. 2026-10-18 03:41 UTCEG score recompute
  8. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  9. 2026-10-17 10:53 UTCEG score recompute
  10. 2026-10-17 10:53 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  12. 2026-10-16 12:30 UTCEG score recompute
  13. 2026-10-16 12:30 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  15. 2026-10-15 14:17 UTCEG score recompute
  16. 2026-10-15 14:17 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  18. 2026-10-14 09:02 UTCEG score recompute
  19. 2026-10-14 09:01 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  21. 2026-10-13 05:43 UTCEG score recompute
  22. 2026-10-13 05:43 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  24. 2026-10-12 16:08 UTCEG score recompute
  25. 2026-10-12 08:01 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
Show 75 more
  1. 2026-10-11 19:50 UTCEG score recompute
  2. 2026-10-11 17:04 UTCEG score recompute
  3. 2026-10-11 14:30 UTCEG score recompute
  4. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  5. 2026-10-11 04:01 UTCOSV refresh
  6. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  7. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  8. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  9. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  10. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  11. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  12. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  13. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  14. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  15. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  16. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  17. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  18. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  19. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  20. 2026-09-21 15:49 UTCOSV refresh
  21. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  22. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  23. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  24. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  25. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  26. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  27. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  28. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  29. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  30. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  31. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  32. 2026-09-02 13:04 UTCOSV refresh
  33. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  34. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  35. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  36. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  37. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  38. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  39. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  40. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  41. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  42. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  43. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  44. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  45. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  46. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  47. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  48. 2026-08-16 09:49 UTCEG score recompute
  49. 2026-08-16 09:49 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  50. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  51. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  52. 2026-08-14 23:47 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  53. 2026-08-14 19:25 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  54. 2026-08-14 14:58 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-08-14 10:36 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  56. 2026-08-14 06:11 UTCEG score recompute
  57. 2026-08-14 06:11 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  58. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  59. 2026-08-13 00:52 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  60. 2026-08-12 20:30 UTCEG score recompute
  61. 2026-08-12 20:30 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  62. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  63. 2026-08-12 01:09 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-08-11 20:41 UTCEG score recompute
  65. 2026-08-11 20:40 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  66. 2026-08-11 08:16 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  67. 2026-08-11 03:41 UTCEG score recompute
  68. 2026-08-11 03:41 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  69. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  70. 2026-08-10 11:59 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  71. 2026-08-10 06:31 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  72. 2026-08-10 02:09 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  73. 2026-08-09 21:46 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-08-09 17:24 UTCEG score recompute
  75. 2026-08-09 17:24 UTCGHSA enrichmentGHSA-q2q4-jjp8-f6m3 · GitHub severity CRITICAL · GitHub CVSS 9.8

Frequently asked(5)

What is CVE-2026-4176?
CVE-2026-4176 is a critical-severity vulnerability; its CVE record was published on March 29, 2026. Perl versions from 5.9.4 before 5.40.4-RC1, from 5.41.0 before 5.42.2-RC1, from 5.43.0 before 5.43.9 contain a vulnerable version of Compress::Raw::Zlib. Compress::Raw::Zlib is included in the Perl package as a dual-life core module, and is vulnerable to CVE-2026-3381 due to a vendored version of…
When was the CVE record for CVE-2026-4176 published?
The CVE record for CVE-2026-4176 was published on March 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 June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-4176 actively exploited?
CVE-2026-4176 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (56th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-4176?
CVE-2026-4176 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-4176?
A fix for CVE-2026-4176 is available: update to the fixed version the vendor names in its advisory. Fixed versions, as the CVE record's CNA (CPAN Security Group) states them: "Update to Perl stable release 5.40.4 or 5.42.2 or later, which include Compress::Raw::Zlib 2.222." The vendor advisories EchelonGraph has for CVE-2026-4176 are linked in the Vendor Advisories panel on this page.

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