CVE-2019-3855

HIGHNVD 8.88.8
EchelonGraph scoreMEDIUM confidence

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

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-13. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this weekElevated
8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 9.3%CVSS: 8.8Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

An integer overflow flaw which could lead to an out of bounds write was discovered in libssh2 before 1.8.1 in the way packets are read from the server. A remote attacker who compromises a SSH server may be able to execute code on the client system when a user connects to the server.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
56
EG Risk 56/100

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)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
9.3%
EPSS %ILE
95th
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 (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
9.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-21). 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (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 21, 2019

Last Modified

October 14, 2026

Advisory Details (8)

Auto-updated Aug 17, 2026
Patch available. Sources: redhat.
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 7.5 Extended Update Support.

https://access.redhat.com/errata/RHSA-2019:1791
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 6.

https://access.redhat.com/errata/RHSA-2019:1652
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2019:1175
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 7.

https://access.redhat.com/errata/RHSA-2019:0679
Web page

oss-security - [SECURITY ADVISORIES] libssh2

http://www.openwall.com/lists/oss-security/2019/03/18/3
Web page

Full Disclosure: APPLE-SA-2019-9-26-7 Xcode 11.0

http://seclists.org/fulldisclosure/2019/Sep/42

Patch Availability(7)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibssh2-1 (1.5.0-2ubuntu0.1+esm1) @ xenial2026-10-21ubuntu
redhatlibssh2-0:1.4.3-11.el7_3.12019-08-07redhat
redhatlibssh2-0:1.4.3-11.el7_4.12019-07-30redhat
redhatlibssh2-0:1.4.3-11.el7_5.12019-07-16redhat
redhatlibssh2-0:1.4.2-3.el6_10.12019-07-02redhat
redhatvirt:rhel-8000020190510171727.55190bc52019-05-14redhat
redhatlibssh2-0:1.4.3-12.el7_6.22019-03-28redhat

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

(22 across 22 ecosystems)
Alpine:v3.10(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.11(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.12(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.13(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.14(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.15(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.16(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.17(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.18(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Alpine:v3.9(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.1-r0: fixed in 1.8.1-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.0-2.1: fixed in 1.8.0-2.1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.0-2.1: fixed in 1.8.0-2.1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.0-2.1: fixed in 1.8.0-2.1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libssh2—
  • every version up to 1.8.0-2.1: fixed in 1.8.0-2.1
—
Debian:8(1)
PackageVulnerable rangeFix by version rangeDependents
libssh21.4.3-4.1, 1.4.3-4.1+deb8u1
  • every version up to 1.4.3-4.1+deb8u2: fixed in 1.4.3-4.1+deb8u2
—
Debian:9(1)
PackageVulnerable rangeFix by version rangeDependents
libssh21.7.0-1
  • every version up to 1.7.0-1+deb9u1: fixed in 1.7.0-1+deb9u1
—

Weakness Classification(2)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 11× in last 7d / 40× 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 96 of 171 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. 4 repeat rows among the latest 100 are merged into the row they repeat. The 75 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 16:27 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  2. 2026-10-22 16:28 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  3. 2026-10-21 17:40 UTCEG score recompute
  4. 2026-10-21 17:40 UTCVendor advisory
  5. 2026-10-21 17:39 UTCGHSA enrichmentGHSA-hhcg-w86v-64g8 · GitHub severity HIGH · GitHub CVSS 8.8
  6. 2026-10-21 16:27 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  7. 2026-10-20 16:28 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  8. 2026-10-19 16:27 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  9. 2026-10-18 16:27 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  10. 2026-10-18 09:45 UTCEG score recompute
  11. 2026-10-17 16:28 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  12. 2026-10-16 16:32 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  13. 2026-10-15 16:27 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  14. 2026-10-14 16:28 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  15. 2026-10-14 07:26 UTCVendor advisory
  16. 2026-10-14 07:26 UTCGHSA enrichmentGHSA-hhcg-w86v-64g8 · GitHub severity HIGH · GitHub CVSS 8.8
  17. 2026-10-14 07:02 UTCEG score recompute
  18. 2026-10-14 07:02 UTCVendor advisory
  19. 2026-10-14 07:02 UTCGHSA enrichmentGHSA-hhcg-w86v-64g8 · GitHub severity HIGH · GitHub CVSS 8.8
  20. 2026-10-13 16:28 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  21. 2026-10-12 19:54 UTCEG score recompute
  22. 2026-10-12 16:28 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  23. 2026-10-12 00:18 UTCEG score recompute
  24. 2026-10-11 13:42 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  25. 2026-10-10 19:56 UTCEPSS rescoreEPSS 9.3% · 95th percentile
Show 71 more
  1. 2026-10-09 20:03 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  2. 2026-10-09 07:28 UTCOSV refresh
  3. 2026-10-08 16:37 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  4. 2026-10-07 23:43 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  5. 2026-10-06 15:13 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  6. 2026-10-05 17:39 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  7. 2026-10-04 23:18 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  8. 2026-10-03 14:22 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  9. 2026-09-30 14:59 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  10. 2026-09-30 10:23 UTCEG score recompute
  11. 2026-09-28 13:46 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  12. 2026-09-27 13:40 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  13. 2026-09-26 15:54 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  14. 2026-09-26 00:20 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  15. 2026-09-24 13:59 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  16. 2026-09-22 14:43 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  17. 2026-09-21 20:28 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  18. 2026-09-19 15:37 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  19. 2026-09-19 14:03 UTCOSV refresh
  20. 2026-09-18 19:23 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  21. 2026-09-17 19:22 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  22. 2026-09-16 14:04 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  23. 2026-09-15 03:06 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  24. 2026-09-13 16:42 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  25. 2026-09-12 14:56 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  26. 2026-09-11 14:48 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  27. 2026-09-11 09:32 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  28. 2026-09-08 21:55 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  29. 2026-09-07 15:57 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  30. 2026-09-06 13:44 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  31. 2026-09-05 15:24 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  32. 2026-09-04 13:56 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  33. 2026-09-02 14:08 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  34. 2026-09-01 03:32 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  35. 2026-08-31 18:04 UTCOSV refresh
  36. 2026-08-30 01:18 UTCEPSS rescoreEPSS 9.3% · 95th percentile
  37. 2026-08-27 14:21 UTCEPSS rescoreEPSS 9.3% · 94th percentile
  38. 2026-08-26 14:42 UTCEPSS rescoreEPSS 9.3% · 94th percentile
  39. 2026-08-25 13:45 UTCEPSS rescoreEPSS 9.3% · 94th percentile
  40. 2026-08-19 17:00 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  41. 2026-08-18 13:44 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  42. 2026-08-15 01:26 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  43. 2026-08-14 21:54 UTCOSV refresh
  44. 2026-08-13 21:57 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  45. 2026-08-12 13:47 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  46. 2026-08-09 13:43 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  47. 2026-08-08 16:33 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  48. 2026-08-07 16:23 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  49. 2026-08-05 19:13 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  50. 2026-08-04 15:05 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  51. 2026-08-04 10:34 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  52. 2026-08-03 10:32 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  53. 2026-08-02 02:23 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  54. 2026-08-01 04:12 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  55. 2026-07-30 16:24 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  56. 2026-07-30 10:44 UTCOSV refresh
  57. 2026-07-30 01:27 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  58. 2026-07-28 15:32 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  59. 2026-07-25 14:14 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  60. 2026-07-24 14:14 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  61. 2026-07-23 14:15 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  62. 2026-07-23 01:45 UTCEG score recompute
  63. 2026-07-22 22:26 UTCEG score recompute
  64. 2026-07-22 14:05 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  65. 2026-07-21 15:22 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  66. 2026-07-20 17:04 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  67. 2026-07-19 14:28 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  68. 2026-07-19 02:26 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  69. 2026-07-18 10:02 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  70. 2026-07-16 16:59 UTCEPSS rescoreEPSS 9.2% · 94th percentile
  71. 2026-07-15 16:55 UTCEPSS rescoreEPSS 9.2% · 94th percentile

Frequently asked(5)

What is CVE-2019-3855?
CVE-2019-3855 is a high-severity vulnerability; its CVE record was published on March 21, 2019. An integer overflow flaw which could lead to an out of bounds write was discovered in libssh2 before 1.8.1 in the way packets are read from the server. A remote attacker who compromises a SSH server may be able to execute code on the client system when a user connects to the server.
When was CVE-2019-3855 made public?
CVE-2019-3855 was made public on March 13, 2019: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on March 21, 2019. EchelonGraph's copy of the record carries a last-modified date of October 14, 2026; the record at its source may have been updated since.
Is CVE-2019-3855 actively exploited?
CVE-2019-3855 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 9.3% probability of exploitation in the next 30 days (95th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2019-3855?
CVE-2019-3855 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2019-3855?
A fix for CVE-2019-3855 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2019-3855 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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