CVE-2026-3945
tinyproxy Integer Overflow in HTTP Chunked Transfer-Encoding Parser Leading to Denial of Service
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol without properly validating overflow conditions (e.g., errno == ERANGE).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.7
tinyproxy Integer Overflow in HTTP Chunked Transfer-Encoding Parser Leading to Denial of Service
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol without properly validating overflow conditions (e.g., errno == ERANGE).
- Record
CVE-2026-3945- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 7.8
AV:N/AC:L/Au:N/C:N/I:N/A:C - Weakness
- CWE-190
- Updated
- 2026-11-02
EUVDEUVD-2026-17066
8.7
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol without properly validating overflow conditions (e.g., errno == ERANGE).
- Record
EUVD-2026-17066- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-6vhj-8f7g-v7f7
8.7
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to...
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol() without properly validating overflow conditions (e.g., errno == ERANGE). A crafted chunk size such as 0x7fffffffffffffff (LONG_MAX) bypasses the existing validation check (chunklen < 0), leading to a signed integer overflow during arithmetic operations (chunklen + 2). This results in incorrect size calculations, causing the proxy to attempt reading an extremely large amount of request-body data and holding worker connections open indefinitely. An attacker can exploit this behavior to exhaust all available worker slots, preventing new connections from being accepted and causing complete service unavailability. Upstream addressed this issue in commit bb7edc4; however, the latest stable release (1.11.3) remains affected at the time of publication.
- Record
GHSA-6vhj-8f7g-v7f7- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-190
- Updated
- 2026-11-02
NVD
8.7
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol without properly validating overflow conditions (e.g., errno == ERANGE).
- Record
CVE-2026-3945- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 7.8 High
AV:N/AC:L/Au:N/C:N/I:N/A:C - Weakness
- CWE-190
- Updated
- 2026-11-02
OSV
8.7
tinyproxy Integer Overflow in HTTP Chunked Transfer-Encoding Parser Leading to Denial of Service
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol without properly validating overflow conditions (e.g., errno == ERANGE).
- Record
CVE-2026-3945- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-190
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-3945
8.7
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol without properly validating overflow conditions (e.g., errno == ERANGE).
- Record
DEBIAN-CVE-2026-3945- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-3945
8.7
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol without properly validating overflow conditions (e.g., errno == ERANGE).
- Record
UBUNTU-CVE-2026-3945- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:10471-1 No score
tinyproxy-1.11.3-2.1 on GA media
These are all security issues fixed in the tinyproxy-1.11.3-2.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:10471-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:20456-1 No score
Security update for tinyproxy
This update for tinyproxy fixes the following issues:
Changes in tinyproxy:
-
CVE-2026-3945: Fixed denial of service by unauthenticated remote attacker (boo#1261024)
-
Update to release 1.11.3
- conf: add BasicAuthRealm feature
- basic auth: fix error status 401 vs 407
- tinyproxy.conf.5: explain what a site_spec looks like
- tinyproxy.conf.5: add an IPv6 example to allow/deny section
- reqs: fix integer overflow in port number processing
- Record
openSUSE-SU-2026:20456-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
tinyproxyDebian:12 |
All versions, plus listed versions 1.11.1-2.11.11.1-2.1+deb12u11.11.1-31.11.1-41.11.2-11.11.2-1~bpo12+11.11.3-11.11.3-1~bpo13+1 |
None known |
tinyproxyDebian:13 |
All versions, plus listed versions 1.11.2-11.11.3-11.11.3-1~bpo13+1 |
None known |
tinyproxyDebian:14 |
All versions, plus listed versions 1.11.2-11.11.3-11.11.3-1~bpo13+1 |
None known |
tinyproxyUbuntu:Pro:14.04:LTS |
All versions, plus listed versions 1.8.3-3ubuntu11.8.3-3ubuntu14.04.1~esm11.8.3-3ubuntu14.04.1~esm21.8.3-3ubuntu14.04.1~esm3 |
None known |
tinyproxyUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 1.8.3-3ubuntu11.8.3-3ubuntu16.04.1~esm11.8.3-3ubuntu16.04.1~esm21.8.3-3ubuntu16.04.1~esm3 |
None known |
tinyproxyUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 1.8.4-21.8.4-31.8.4-51.8.4-5ubuntu0.1~esm11.8.4-5ubuntu0.1~esm21.8.4-5ubuntu0.1~esm3 |
None known |
tinyproxyUbuntu:20.04:LTS |
All versions, plus listed versions 1.10.0-21.10.0-41.10.0-4ubuntu0.11.10.0-4ubuntu0.2 |
None known |
tinyproxyUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 1.10.0-51.11.0-11.11.0-1ubuntu0.1~esm11.11.0-1ubuntu0.1~esm2 |
None known |
tinyproxyUbuntu:24.04:LTS |
All versions, plus listed versions 1.11.1-2.11.11.1-31.11.1-3ubuntu0.1 |
None known |
tinyproxyUbuntu:25.10 |
All versions, plus listed versions 1.11.2-1 |
None known |
Show 4 moreShow less
| Package | Affected | Fixed |
|---|---|---|
tinyproxyUbuntu:26.10 |
All versions, plus listed versions 1.11.3-1 |
None known |
tinyproxyUbuntu:26.04:LTS |
All versions, plus listed versions 1.11.2-11.11.2-1build11.11.3-1 |
None known |
tinyproxyopenSUSE:Tumbleweed |
before 1.11.3-2.1 | 1.11.3-2.1 |
tinyproxyopenSUSE:Leap 16.0 |
before 1.11.3-bp160.1.1 | 1.11.3-bp160.1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-3945 is a high vulnerability (CVSS 8.7) in Tinyproxy, published March 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.60%, the 49th percentile. Fixed in tinyproxy 1.11.3-2.1.
References
github.com/tinyproxy/tinyproxy/issues/602
github.com/tinyproxy/tinyproxy/pull/603
github.com/tinyproxy/tinyproxy/commit/969852c
github.com/tinyproxy/tinyproxy/commit/bb7edc4
github.com/tinyproxy/tinyproxy/releases
nvd.nist.gov/vuln/detail/CVE-2026-3945