curl: URL unescape heap overflow via integer truncation
Published Jul 31, 2018
9.8
CRITICALCVSS 3.0
EPSS 4.67%
Description
The URL percent-encoding decode function in libcurl before 7.51.0 is called `curl_easy_unescape`. Internally, even if this function would be made to allocate a unscape destination buffer larger than 2GB, it would return that new length in a signed 32 bit integer variable, thus the length would get either just truncated or both truncated and turned negative. That could then lead to libcurl writing outside of its heap based buffer.
Affected products
-
- Version 7.51.0StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| The Curl Project | Curl | n/a |
|
No data.
Red Hat JBoss Core Services
jbcs-httpd24-curl
Fixed · RHSA-2018:2486
Red Hat Software Collections for Red Hat Enterprise Linux 6
httpd24-curl-0:7.61.1-1.el6
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 6
httpd24-httpd-0:2.4.34-7.el6
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 6
httpd24-nghttp2-0:1.7.1-7.el6
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7
httpd24-curl-0:7.61.1-1.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7
httpd24-httpd-0:2.4.34-7.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7
httpd24-nghttp2-0:1.7.1-7.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
httpd24-curl-0:7.61.1-1.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
httpd24-httpd-0:2.4.34-7.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
httpd24-nghttp2-0:1.7.1-7.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
httpd24-curl-0:7.61.1-1.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
httpd24-httpd-0:2.4.34-7.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
httpd24-nghttp2-0:1.7.1-7.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
httpd24-curl-0:7.61.1-1.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
httpd24-httpd-0:2.4.34-7.el7
Fixed · RHSA-2018:3558
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
httpd24-nghttp2-0:1.7.1-7.el7
Fixed · RHSA-2018:3558
.NET Core 1.0 on Red Hat Enterprise Linux
rh-dotnetcore10-curl
Out of support scope
.NET Core 1.1 on Red Hat Enterprise Linux
rh-dotnetcore11-curl
Out of support scope
.NET Core 2.0 on Red Hat Enterprise Linux
rh-dotnet20-curl
Out of support scope
.NET Core 2.1 on Red Hat Enterprise Linux
rh-dotnet21-curl
Will not fix
Red Hat Enterprise Linux 5
curl
Not affected
Red Hat Enterprise Linux 6
curl
Not affected
Red Hat Enterprise Linux 7
curl
Will not fix
Red Hat Enterprise Virtualization 3
mingw-virt-viewer
Will not fix
Red Hat JBoss Enterprise Web Server 3
curl
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat JBoss Core Services | jbcs-httpd24-curl | Fixed | RHSA-2018:2486 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | httpd24-curl-0:7.61.1-1.el6 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | httpd24-httpd-0:2.4.34-7.el6 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | httpd24-nghttp2-0:1.7.1-7.el6 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | httpd24-curl-0:7.61.1-1.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | httpd24-httpd-0:2.4.34-7.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | httpd24-nghttp2-0:1.7.1-7.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | httpd24-curl-0:7.61.1-1.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | httpd24-httpd-0:2.4.34-7.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | httpd24-nghttp2-0:1.7.1-7.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | httpd24-curl-0:7.61.1-1.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | httpd24-httpd-0:2.4.34-7.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | httpd24-nghttp2-0:1.7.1-7.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | httpd24-curl-0:7.61.1-1.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | httpd24-httpd-0:2.4.34-7.el7 | Fixed | RHSA-2018:3558 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | httpd24-nghttp2-0:1.7.1-7.el7 | Fixed | RHSA-2018:3558 |
| .NET Core 1.0 on Red Hat Enterprise Linux | rh-dotnetcore10-curl | Out of support scope | n/a |
| .NET Core 1.1 on Red Hat Enterprise Linux | rh-dotnetcore11-curl | Out of support scope | n/a |
| .NET Core 2.0 on Red Hat Enterprise Linux | rh-dotnet20-curl | Out of support scope | n/a |
| .NET Core 2.1 on Red Hat Enterprise Linux | rh-dotnet21-curl | Will not fix | n/a |
| Red Hat Enterprise Linux 5 | curl | Not affected | n/a |
| Red Hat Enterprise Linux 6 | curl | Not affected | n/a |
| Red Hat Enterprise Linux 7 | curl | Will not fix | n/a |
| Red Hat Enterprise Virtualization 3 | mingw-virt-viewer | Will not fix | n/a |
| Red Hat JBoss Enterprise Web Server 3 | curl | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
AV:N/AC:L/Au:N/C:P/I:P/A:P
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
PartialDecision
n/aAssessed Apr 15, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (13 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 4.67% (0.04670) | 91.48th | v5 (v2026.06.15) |
| Jun 15, 2026 | 4.71% (0.04709) | 90.63th | v5 (v2026.06.15) |
| Feb 14, 2026 | 1.21% (0.01209) | 78.66th | v4 (v2025.03.14) |
| Mar 17, 2025 | 2.25% (0.02254) | 83.43th | v4 (v2025.03.14) |
| Dec 12, 2024 | 1.29% (0.01290) | 86.38th | v3 (v2023.03.01) |
| Jan 31, 2024 | 1.27% (0.01272) | 84.28th | v3 (v2023.03.01) |
| Dec 22, 2023 | 1.19% (0.01185) | 83.51th | v3 (v2023.03.01) |
| Jul 25, 2023 | 1.26% (0.01260) | 83.80th | v3 (v2023.03.01) |
| Mar 7, 2023 | 1.02% (0.01020) | 81.46th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.54% (0.01537) | 74.52th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.54% (0.01537) | 74.48th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.54% (0.01537) | 72.41th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.54% (0.01537) | 51.33th | v2 (v2022.01.01) |
References (13)
- http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html x_refsource_CONFIRM
- http://www.securityfocus.com/bid/94105 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1037192 vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry
- https://access.redhat.com/errata/RHSA-2018:2486 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2018:3558 vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2016-8622 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1388386 Issue Tracking
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-8622 x_refsource_CONFIRMIssue TrackingPatchThird Party Advisory
- https://curl.haxx.se/docs/adv_20161102H.html x_refsource_CONFIRMPatchVendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2016-8622
- https://security.gentoo.org/glsa/201701-47 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2016-8622
- https://www.tenable.com/security/tns-2016-21 x_refsource_CONFIRMThird Party Advisory
Change history (0)
No recorded changes yet.