CVE-2019-3856: debian debian_linux Integer Overflow or Wraparound
Vulnerability summary
CVE-2019-3856 is a high (CVSS 8.8) Integer Overflow or Wraparound vulnerability in debian debian_linux. EPSS estimates a 6.13% chance of exploitation in the next 30 days, higher than 93.4% of scored vulnerabilities.
Not severe (CVSS 7.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 18 · Related 9Timeline
- 25-03-2019PublishedVulnerability first disclosed.
- 14-10-2026Last modifiedVulnerability information updated.
Description
An integer overflow flaw, which could lead to an out of bounds write, was discovered in libssh2 before 1.8.1 in the way keyboard prompt requests are parsed. 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 metrics
8 scores · 5 sources · 3 versions- OSV · AlpineEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- NVDNIST7.5HighCVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
6.13%
Chance of exploitation in the next 30 days
Percentile
93%
Versus all other CVEs
30-day change
No change 0.00 pp
From 6.13% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Redhat7 products
- enterprise_linux8.0
- enterprise_linux_desktop7.0
- enterprise_linux_server7.0
- enterprise_linux_server_aus7.6
- enterprise_linux_server_eus7.6
Debian2 products
- libssh2< 1.8.0-2.1
- debian_linuxEOL8.0 | 9.0
Alpine1 product
- libssh2< 1.8.1-r0
Fedoraproject1 product
- fedoraEOL28
Libssh21 product
- libssh2< 1.8.1
Netapp1 product
Opensuse1 product
- leapEOL15.0 | 42.3
Oracle1 product
- peoplesoft_enterprise_peopletools8.56 | 8.57
The libssh2 project1 product
- libssh21.8.1
Ubuntu1 product
- libssh2< 1.4.3-2ubuntu0.2+esm2 | < 1.5.0-2ubuntu0.1+esm1 | All versions (No fix recorded)
10 vendors · 17 products
References
23 links- bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3856X Refsource CONFIRMIssue TrackingPatchThird Party Advisory
lists.debian.org/debian-lts-announce/2019/03/msg00032.htmlMailing ListX Refsource MLISTThird Party Advisory- lists.opensuse.org/opensuse-security-announce/2019-03/msg00040.htmlVendor AdvisoryX Refsource SUSEMailing ListThird Party Advisory
- lists.opensuse.org/opensuse-security-announce/2019-04/msg00003.htmlVendor AdvisoryX Refsource SUSEThird Party Advisory
Show all 23 references
- www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.htmlX Refsource MISCPatchThird Party Advisory