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    CVE-2020-26137

    urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.

    Published:Feb 10, 2020
    Last Modified:Nov 21, 2024
    EPS:Sep 29, 2020
    EPSS Score:0.00245
    CVSS Score:6.5

    Affected Products

    Vendor
    Canonical
    Product
    Ubuntu Linux
    Vendor
    Debian
    Product
    Debian Linux
    Vendor
    Oracle
    Product
    Communications Cloud Native Core Network Function Cloud Native Environment
    Vendor
    Oracle
    Product
    Zfs Storage Appliance Kit
    Vendor
    Python
    Product
    Urllib3
    Vendor
    Redhat
    Product
    Enterprise Linux
    Vendor
    Redhat
    Product
    Openshift
    Vendor
    Redhat
    Product
    Rhel Software Collections

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-10 Buffer Overflow via Environment Variables
    CAPEC-101 Server Side Include (SSI) Injection
    CAPEC-105 HTTP Request Splitting
    CAPEC-108 Command Line Execution through SQL Injection
    CAPEC-120 Double Encoding
    CAPEC-13 Subverting Environment Variable Values
    CAPEC-135 Format String Injection
    CAPEC-14 Client-side Injection-induced Buffer Overflow
    CAPEC-24 Filter Failure through Buffer Overflow
    CAPEC-250 XML Injection
    CAPEC-267 Leverage Alternate Encoding
    CAPEC-273 HTTP Response Smuggling
    CAPEC-28 Fuzzing
    CAPEC-3 Using Leading 'Ghost' Character Sequences to Bypass Input Filters
    CAPEC-31 Accessing/Intercepting/Modifying HTTP Cookies
    CAPEC-34 HTTP Response Splitting
    CAPEC-42 MIME Conversion
    CAPEC-43 Exploiting Multiple Input Interpretation Layers
    CAPEC-45 Buffer Overflow via Symbolic Links
    CAPEC-46 Overflow Variables and Tags
    CAPEC-47 Buffer Overflow via Parameter Expansion
    CAPEC-51 Poison Web Service Registry
    CAPEC-52 Embedding NULL Bytes
    CAPEC-53 Postfix, Null Terminate, and Backslash
    CAPEC-6 Argument Injection
    CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic
    CAPEC-67 String Format Overflow in syslog()
    CAPEC-7 Blind SQL Injection
    CAPEC-71 Using Unicode Encoding to Bypass Validation Logic
    CAPEC-72 URL Encoding
    CAPEC-76 Manipulating Web Input to File System Calls
    CAPEC-78 Using Escaped Slashes in Alternate Encoding
    CAPEC-79 Using Slashes in Alternate Encoding
    CAPEC-8 Buffer Overflow in an API Call
    CAPEC-80 Using UTF-8 Encoding to Bypass Validation Logic
    CAPEC-83 XPath Injection
    CAPEC-84 XQuery Injection
    CAPEC-85 AJAX Footprinting
    CAPEC-9 Buffer Overflow in Local Command-Line Utilities

    Related CVEs

    CVE-2026-13476 (CVSS 7.3) — IBM Informix Dynamic Server 14.10, 15.0, and 12.10 could allow an unauthenticated user to execute arbitrary co…
    CVE-2026-13367 (CVSS 7.8) — IBM Informix Dynamic Server 14.10, and 15.0 contain a local privilege escalation vulnerability in the oninit s…
    CVE-2026-47337 (CVSS 3.3) — Ubuntu Linux 6.8, 6.17 and 7.0 contain SAUCE patches with a possible NULL pointer dereference in the handling …
    CVE-2026-47336 (CVSS 3.3) — Ubuntu Linux 6.8 contains SAUCE patches with a possible use of an uninitialized variable in AppArmor AF_INET/A…
    CVE-2026-47335 (CVSS 5.5) — Ubuntu Linux 6.8 contains SAUCE patches with a possible NULL pointer dereference in the handling of AppArmor n…
    CVE-2026-47334 (CVSS 5.5) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which incorrectly sleep while holding a spinlock…
    CVE-2026-47333 (CVSS 7.8) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which can potentially incorrectly compute the si…
    CVE-2026-47332 (CVSS 5.5) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which incorrectly validate the size of an intern…
    CVE-2026-47331 (CVSS 7.8) — Ubuntu Linux 6.8 contains AppArmor SAUCE patches which fail to acquire a lock when modifying a linked list. An…
    CVE-2026-47330 (CVSS 3.3) — Ubuntu Linux 6.8, 7.17 and 7.0 contain AppArmor SAUCE patches which can, under certain circumstances, use an u…

    References

    https://bugs.python.org/issue39603
    https://github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436b
    https://github.com/urllib3/urllib3/pull/1800
    https://lists.debian.org/debian-lts-announce/2021/06/msg00015.html
    https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html
    https://usn.ubuntu.com/4570-1/
    https://www.oracle.com/security-alerts/cpujul2022.html
    https://www.oracle.com/security-alerts/cpuoct2021.html
    https://bugs.python.org/issue39603
    https://github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436b
    https://github.com/urllib3/urllib3/pull/1800
    https://lists.debian.org/debian-lts-announce/2021/06/msg00015.html
    https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html
    https://usn.ubuntu.com/4570-1/
    https://www.oracle.com/security-alerts/cpujul2022.html
    https://www.oracle.com/security-alerts/cpuoct2021.html

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High