LiveActive security incident?Get immediate response
CVE Record

CVE-2023-35934: yt-dlp File Downloader cookie leak

yt-dlp is a command-line program to download videos from video sites. During file downloads, yt-dlp or the external downloaders that yt-dlp employs may leak cookies on HTTP redirects to a different host, or leak them when the host for download fragments differs from their parent manifest's host. This vulnerable behavior is present in yt-dlp prior to 2023.07.06 and nightly 2023.07.06.185519. All native and external downloaders are affected, except for `curl` and `httpie` (version 3.1.0 or later). At the file download stage, all cookies are passed by yt-dlp to the file downloader as a `Cookie` header, thereby losing their scope. This also occurs in yt-dlp's info JSON output, which may be used by external tools. As a result, the downloader or external tool may indiscriminately send cookies with requests to domains or paths for which the cookies are not scoped. yt-dlp version 2023.07.06 and nightly 2023.07.06.185519 fix this issue by removing the `Cookie` header upon HTTP redirects; having native downloaders calculate the `Cookie` header from the cookiejar, utilizing external downloaders' built-in support for cookies instead of passing them as header arguments, disabling HTTP redirectiong if the external downloader does not have proper cookie support, processing cookies passed as HTTP headers to limit their scope, and having a separate field for cookies in the info dict storing more information about scoping Some workarounds are available for those who are unable to upgrade. Avoid using cookies and user authentication methods. While extractors may set custom cookies, these usually do not contain sensitive information. Alternatively, avoid using `--load-info-json`. Or, if authentication is a must: verify the integrity of download links from unknown sources in browser (including redirects) before passing them to yt-dlp; use `curl` as external downloader, since it is not impacted; and/or avoid fragmented formats such as HLS/m3u8, DASH/mpd and ISM.

MediumCVSS 6.1Not KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

yt-dlp could send authentication cookies to the wrong website during downloads that redirect or split media fragments across hosts. That can expose session cookies when a user downloads content from an untrusted or manipulated source. The issue is fixed in yt-dlp 2023.07.06 and nightly 2023.07.06.185519.

Executive priority

Treat this as a moderate confidentiality issue. Prioritize developer workstations, automation hosts, and media-processing services that use authenticated yt-dlp downloads. It should be fixed promptly where cookies are used, but the source evidence does not support emergency active-exploitation handling.

Technical view

Before fixed versions, yt-dlp passed all cookies to file downloaders as a Cookie header, stripping scope information. Native and most external downloaders could then reuse those cookies across redirects or fragment hosts outside the original cookie scope. The advisory also notes exposure through info JSON used by external tools.

Likely exposure

Exposure is most likely where yt-dlp is used with cookies, browser-imported authentication, info JSON workflows, external downloaders, redirects, or fragmented formats such as HLS, DASH, or ISM. Unauthenticated downloads are lower concern. curl and httpie 3.1.0 or later were identified as exceptions.

Exploitation context

The source bundle does not report known active exploitation and CISA KEV is false. Abuse would require user interaction and a download flow that causes cookies to be sent to a different host or path than intended. The impact is confidentiality loss, not code execution.

Researcher notes

The vulnerable pattern is cookie scope loss at the file download stage. The fix set removes Cookie headers on redirects, computes cookies from the cookiejar for native downloaders, uses external downloader cookie support, blocks unsafe redirects for unsupported tools, and stores scoped cookie details separately in info data.

Mitigation direction

  • Upgrade yt-dlp to 2023.07.06 or later.
  • Upgrade nightly builds to 2023.07.06.185519 or later.
  • Avoid cookies and authenticated downloads until upgraded.
  • Avoid --load-info-json where untrusted download metadata is involved.
  • Use curl as the external downloader if upgrade is temporarily impossible.
  • Avoid fragmented formats when authenticated downloading cannot be avoided.

Validation and detection

  • Inventory installed yt-dlp and yt-dlp nightly versions.
  • Identify automation that passes cookies, browser sessions, or info JSON to yt-dlp.
  • Review external downloader configuration for non-exempt tools.
  • Check package manager advisories for distro-maintained yt-dlp builds.
  • Confirm download workflows no longer pass raw Cookie headers across hosts.
Prepared
Confidence
high
Sources
9

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-200: Information exposure and cloud metadata lookup

Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2023-35934 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
11Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.1CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N1.64Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.1Medium
CVSS 3.1 vector shape for CVE-2023-35934Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
yt-dlpyt-dlpyt-dlp < 2023.07.06, yt-dlp < nightly 2023.07.06.185519Listed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-200 · source CWE mapping

Exposure of Sensitive Information to an Unauthorized Actor

Exposure of Sensitive Information to an Unauthorized Actor represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.