CVE-2019-5436
Public on
Last Modified:
Description
The CVE Program describes this issue as:
A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through 7.64.1.
Statement
This flaw exists if the user selects to use a "blksize" of 504 or smaller (default is 512). The smaller size that is used, the larger the possible overflow becomes. Users choosing a smaller size than default should be rare as the primary use case for changing the size is to make it larger. It is rare for users to use TFTP across the Internet. It is most commonly used within local networks.
Additional information
- Bugzilla 1710620: curl: TFTP receive heap buffer overflow in tftp_receive_packet() function
- CWE-122: Heap-based Buffer Overflow
- FAQ: Frequently asked questions about CVE-2019-5436
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
Red Hat | NVD | |
---|---|---|
CVSS v3 Base Score | 7 | 7.8 |
Attack Vector | Local | Local |
Attack Complexity | High | Low |
Privileges Required | Low | Low |
User Interaction | None | None |
Scope | Unchanged | Unchanged |
Confidentiality Impact | High | High |
Integrity Impact | High | High |
Availability Impact | High | High |
CVSS v3 Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
A successful attacker requires the curl client to chose a non-default "blksize" of 504 or smaller (default is 512 and it is unusual to reduce the blksize. The primary use case of changing the size is to make it larger and not smaller). Therefore this flaw has been classified as having an Attack Complexity of High (AC:H)
Acknowledgements
Red Hat would like to thank the Curl project for reporting this issue. Upstream acknowledges l00p3r as the original reporter.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Open a support case to request a prioritization of releasing a fix for this vulnerability.
What can I do if my product is listed as "Fix deferred"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Apply a mitigation (if one exists).
- Open a support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.